US11956754B2 - Method for operating terminal and base station in wireless communication system supporting NB-IoT, and apparatus supporting - Google Patents

Method for operating terminal and base station in wireless communication system supporting NB-IoT, and apparatus supporting Download PDF

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US11956754B2
US11956754B2 US17/267,472 US201917267472A US11956754B2 US 11956754 B2 US11956754 B2 US 11956754B2 US 201917267472 A US201917267472 A US 201917267472A US 11956754 B2 US11956754 B2 US 11956754B2
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nrs
base station
iot
subframe
transmission
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US20210329591A1 (en
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Seunggye HWANG
Changhwan Park
Joonkui AHN
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LG Electronics Inc
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LG Electronics Inc
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W68/00—User notification, e.g. alerting and paging, for incoming communication, change of service or the like
    • H04W68/005—Transmission of information for alerting of incoming communication
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/1607—Details of the supervisory signal
    • H04L1/1642—Formats specially adapted for sequence numbers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H04L5/0051—Allocation of pilot signals, i.e. of signals known to the receiver of dedicated pilots, i.e. pilots destined for a single user or terminal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0078—Timing of allocation
    • H04L5/0082—Timing of allocation at predetermined intervals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/80—Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W68/00—User notification, e.g. alerting and paging, for incoming communication, change of service or the like
    • H04W68/02—Arrangements for increasing efficiency of notification or paging channel
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0003—Two-dimensional division
    • H04L5/0005—Time-frequency
    • H04L5/0007—Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT
    • H04L5/001—Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT the frequencies being arranged in component carriers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/70—Services for machine-to-machine communication [M2M] or machine type communication [MTC]

Definitions

  • the present disclosure relates to a wireless communication system supporting Narrowband Internet of Things (NB-IoT) and, more particularly, to operating methods for a terminal and a base station in the wireless communication system and apparatuses supporting the same.
  • NB-IoT Narrowband Internet of Things
  • a wireless communication system is developing to diversely cover a wide range to provide such a communication service as an audio communication service, a data communication service and the like.
  • the wireless communication is a sort of a multiple access system capable of supporting communications with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.).
  • the multiple access system may include one of CDMA (code division multiple access) system, FDMA (frequency division multiple access) system, TDMA (time division multiple access) system, OFDMA (orthogonal frequency division multiple access) system, SC-FDMA (single carrier frequency division multiple access) system and the like.
  • MTC massive machine type communications
  • the object of the present disclosure is to provide operating methods for a terminal (user equipment) and a base station in a wireless communication system supporting Narrowband Internet of Things (NB-IoT) and apparatuses supporting the same.
  • NB-IoT Narrowband Internet of Things
  • the present disclosure provides operating methods for a user equipment (UE) and a base station in a wireless communication system supporting Narrowband Internet of Things (NB-IoT) and apparatuses supporting the same.
  • UE user equipment
  • NB-IoT Narrowband Internet of Things
  • a method for operating a UE in a wireless communication system supporting NB-IoT may include: determining a time period for receiving a narrowband reference signal (NRS) on a non-anchor carrier used for paging; and receiving the NRS within the time period.
  • the time period may be determined based on a specific paging occasion (PO) among a plurality of POs related to the UE.
  • PO paging occasion
  • the specific PO may be a PO having an odd subframe number among the plurality of POs.
  • the specific PO may be a PO having an odd subframe number and an even system frame number (SFN) among the plurality of POs.
  • SFN system frame number
  • the specific PO may be a PO having an even subframe number and an odd SFN among the plurality of POs.
  • the specific PO may be a PO in which the remainder of dividing S by R is equal to the remainder of dividing Q+1 by 2 among the plurality of POs, where S is the SFN of the PO, R is a value preconfigured by a higher layer signal, and Q is the subframe number of the PO.
  • R may be determined based on a ratio between the number of frames and the number of POs.
  • R may be 2, and in a case where that the number of POs in one frame is smaller than 2, R may be 1.
  • the specific PO may be a PO in which the remainder of dividing S by R is equal to the remainder of dividing Q+a by 2 among the plurality of POs, where S is the SFN of the PO, R is a value preconfigured by a higher layer signal, Q is the subframe number of the PO, and a is 0 or 1.
  • a may be determined as 1, and in a case where the number of POs in one frame is greater than 1, a may be determined as 0 or 1 based on a SFN of the specific PO.
  • the specific PO may be a PO with a subframe number of 9 among the plurality of POs.
  • the reception of the NRS within the time period may be determined independently from a paging transmission.
  • a UE in a wireless communication system supporting NB-IoT may include: at least one radio frequency (RF) module; at least one processor; and at least one memory operably connected to the at least one processor and configured to store instructions executable by the at least one processor to perform specific operations.
  • the specific operations may include: determining a time period for receiving an NRS on a non-anchor carrier used for paging; and receiving the NRS within the time period.
  • the time period may be determined based on a specific PO among a plurality of POs related to the UE, and the reception of the NRS within the time period may be independent of the presence of a paging transmission.
  • the specific PO may be a PO in which the remainder of dividing S by R is equal to the remainder of dividing Q+1 by 2 among the plurality of POs, S is the SFN of the PO, R is a value preconfigured by a higher layer signal, and Q is the subframe number of the PO.
  • the UE may communicate with at least one of a mobile terminal, a network, or an autonomous driving vehicle other than a vehicle including the UE.
  • a base station for transmitting a downlink signal in a wireless communication system supporting NB-IoT.
  • the base station may include: at least one RF module; at least one processor; and at least one memory operably connected to the at least one processor and configured to store instructions executable by the at least one processor to perform a specific operation.
  • the specific operation may include transmitting, to a UE, an NRS on a non-anchor carrier used for paging within a specific time period.
  • the specific time period may be determined based on a specific PO among a plurality of POs related to the UE, and the transmission of the NRS within the specific time period may be independent of the presence of a paging transmission.
  • the specific PO may be a PO in which the remainder of dividing S by R is equal to the remainder of dividing Q+1 by 2 among the plurality of POs, where S is the SFN of the PO, R is a value preconfigured by a higher layer signal, and Q is the subframe number of the PO.
  • a user equipment may assume that at least one of a narrowband reference signal (NRS) and a cell-specific reference signal (CRS) is transmitted on a non-anchor carrier (e.g., non-anchor carrier managed for paging) and then receive the corresponding signal.
  • a base station may transmit the corresponding reference signal to the UE on the non-anchor carrier based on the assumption of the UE.
  • the UE may perform monitoring (e.g., radio resource management (RRM) measurement) on the non-anchor carrier based on the corresponding reference signal.
  • monitoring e.g., radio resource management (RRM) measurement
  • UE operations e.g., RRM measurement, etc.
  • RRM measurement e.g., RRM measurement, etc.
  • the UE may assume and receive a reference signal on a paging occasion (PO) among multiple POs, thereby reducing monitoring overhead of the UE.
  • PO paging occasion
  • FIG. 1 illustrates an example of the 3rd Generation Partnership Project (3GPP) Long-Term Evolution (LTE) system architecture.
  • 3GPP 3rd Generation Partnership Project
  • LTE Long-Term Evolution
  • FIG. 2 illustrates an example of the 3GPP New Radio (NR) system architecture.
  • NR New Radio
  • FIG. 3 illustrates physical channels and a general signal transmission method using the physical channels applicable to implementations of the present disclosure.
  • FIG. 4 is a diagram illustrating the structure of a radio frame in an LTE system to which implementations of the present disclosure are applicable.
  • FIG. 5 is a diagram illustrating the structure of a slot in the LTE system to which implementations of the present disclosure are applicable.
  • FIG. 6 is a diagram illustrating the structure of a downlink (DL) subframe in the LTE system to which implementations of the present disclosure are applicable.
  • FIG. 7 is a diagram illustrating the structure of an uplink (UL) subframe in the LTE system to which implementations of the present disclosure are applicable.
  • FIG. 8 is a diagram illustrating the structure of a radio frame in a NR system to which implementations of the present disclosure are applicable.
  • FIG. 9 is a diagram illustrating the structure of a slot in the NR system to which implementations of the present disclosure are applicable.
  • FIG. 10 is a diagram illustrating the structure of a self-contained slot in the NR system to which implementations of the present disclosure are applicable.
  • FIG. 11 illustrates examples of narrowband operations and frequency diversity.
  • FIG. 12 illustrates physical channels available in machine type communications (MTC) and a general signal transmission method using the same.
  • MTC machine type communications
  • FIG. 13 illustrates an example of system information transmissions in MTC.
  • FIG. 14 illustrates an example of scheduling for each of MTC and legacy LTE.
  • FIGS. 15 and 16 illustrate examples of a Narrowband Internet of Things (NB-IoT) frame structure depending on subcarrier spacings.
  • NB-IoT Narrowband Internet of Things
  • FIG. 17 illustrates an example of a resource grid for NB-IoT UL.
  • FIG. 18 illustrates operation modes supported in an NB-IoT system.
  • FIG. 19 illustrates physical channels available in NB-IoT and a general signal transmission method using the same.
  • FIG. 20 illustrates an initial access (IA) procedure applicable to the NB-IoT system.
  • FIG. 21 illustrates a random access procedure applicable to the NB-IoT system.
  • FIG. 22 illustrates an example of discontinuous reception (DRX) mode in an idle and/or inactive state.
  • FIG. 23 illustrates an example of a DRX configuration and indication procedure for an NB-IoT UE.
  • FIG. 24 is a diagram schematically illustrating cell-specific reference signal (CRS) patterns applicable to the present disclosure.
  • FIG. 25 is a diagram schematically illustrating narrowband reference signal (NRS) patterns applicable to the present disclosure.
  • NSS narrowband reference signal
  • FIG. 26 is a flowchart schematically illustrating an operating method for a base station applicable to the present disclosure.
  • FIG. 27 is a flowchart schematically illustrating an operating method for a user equipment (UE) applicable to the present disclosure.
  • UE user equipment
  • FIG. 28 is a diagram schematically illustrating an NRS transmission and reception method according to an implementation of the present disclosure.
  • FIG. 29 is a diagram schematically illustrating an NRS transmission and reception method according to an implementation of the present disclosure.
  • FIG. 30 is a flowchart schematically illustrating a method for a UE to receive an NRS according to an implementation of the present disclosure.
  • FIG. 31 is a flowchart schematically illustrating an NRS transmission and reception method between a UE and base station according to an implementation of the present disclosure.
  • FIG. 32 illustrates a communication system applicable to the present disclosure.
  • FIG. 33 illustrates a wireless device applicable to the present disclosure.
  • FIG. 34 illustrates another example of a wireless device applicable to the present disclosure.
  • FIG. 35 illustrates a hand-held device applicable to the present disclosure.
  • FIG. 36 illustrates a vehicle or an autonomous driving vehicle applicable to the present disclosure.
  • FIG. 37 illustrates a vehicle applicable to the present disclosure.
  • the base station may refer to a terminal node of a network configured to directly communicate with the mobile station. In some cases, specific operations described as performed by the base station in this document may be performed by an upper node of the base station.
  • base station In the network including a plurality of network nodes including the base station, various operations performed for communication with the mobile station may be performed by the base station or other network nodes except the base station.
  • base station is interchangeable with a fixed station, a Node B, an evolved Node B (eNB), a gNode B (gNB), advanced base station (ABS), an access point, etc.
  • eNB evolved Node B
  • gNB gNode B
  • ABS advanced base station
  • access point etc.
  • terminal is interchangeable with a user equipment (UE), a mobile station (MS), a subscriber station (SS), a mobile subscriber station (MSS), a mobile terminal, an advance mobile station (AMS), etc.
  • UE user equipment
  • MS mobile station
  • SS subscriber station
  • MSS mobile subscriber station
  • AMS advance mobile station
  • a transmitting end refers to a fixed and/or mobile node that transmits data or voice services
  • a receiving end refers to a fixed and/or mobile node that receive data or voice services.
  • the mobile and base stations may correspond to the transmitting and receiving ends, respectively.
  • the mobile and base stations may correspond to the receiving and transmitting ends, respectively.
  • the implementations of the present disclosure may be supported by standard specifications disclosed for at least one of wireless access systems including: the Institute of Electrical and Electronics Engineers (IEEE) 802.xx, 3rd Generation Partnership Project (3GPP), 3GPP Long-Term Evolution (LTE), 3GPP Fifth Generation (5G) New Radio (NR), or 3GPP2.
  • 3GPP 3rd Generation Partnership Project
  • 3GPP 3rd Generation Partnership Project
  • LTE 3rd Generation Partnership Project
  • 5G Fifth Generation
  • NR Fifth Generation
  • 3GPP2 3rd Generation Partnership Project 2
  • 3GPP TS 36.213 3GPP TS 36.321, 3GPP TS 36.331
  • CDMA code division multiple access
  • FDMA frequency division multiple access
  • TDMA time division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single carrier-frequency division multiple access
  • the LTE refers to the technology beyond 3GPP technical specification (TS) 36.xxx Release 8.
  • TS Technical specification
  • the LTE technology beyond 3GPP TS 36.xxx Release 10 is referred to as the LTE-A
  • 3GPP TS 38.xxx Release 15 is referred to as the LTE-A pro.
  • the 3GPP NR refers to the technology beyond 3GPP TS 38.xxx Release 15.
  • the LTE/NR may be called ‘3GPP system’.
  • “xxx” refers to a standard specification number.
  • the LTE/NR may be commonly referred to as ‘3GPP system’. Details of the background, terminology, abbreviations, etc. used herein may be found in documents published before the present disclosure. For example, the following documents may be referenced.
  • FIG. 1 illustrates an example of the 3GPP LTE system architecture.
  • a wireless communication system may be referred to as an evolved-UMTS terrestrial radio access network (E-UTRAN) or a long term evolution (LTE)/LTE-A system.
  • the E-UTRAN includes at least one base station that provides control and user planes to a UE.
  • the UE may be fixed or mobile.
  • the UE may be referred to as another terminology such as ‘mobile station (MS)’, ‘user terminal (UT)’, ‘subscriber station (SS)’, ‘mobile terminal (MT)’, or ‘wireless device’.
  • the base station may be a fixed station that communicates with the UE.
  • the base station may be referred to as another terminology such as ‘evolved Node-B (eNB)’, ‘general Node-B (gNB)’, ‘base transceiver system (BTS)’, or ‘access point (AP)’.
  • the base stations may be interconnected through an X 2 interface.
  • the base station may be connected to an evolved packet core (EPC) through an S 1 interface. More particularly, the base station may be connected to a mobility management entity (MME) through S 1 -MME and to a serving gateway (S-GW) through S 1 -U.
  • EPC includes the MME, the S-GW, and a packet data network-gateway (P-GW).
  • Radio interface protocol layers between the UE and network may be classified into Layer 1 (L1), Layer 2 (L2), and Layer 3 (L3) based on three lower layers of the open system interconnection (OSI) model well known in communication systems.
  • a physical (PHY) layer which belongs to L1, provides an information transfer service over a physical channel.
  • a radio resource control (RRC) layer which belongs to L3, controls radio resources between the UE and network. To this end, the base station and UE may exchange an RRC message through the RRC layer.
  • FIG. 2 illustrates an example of the 3GPP NR system architecture.
  • a NG-RAN includes gNBs, each of which provides a NG-RA user plane (e.g., new AS sublayer/PDCP/RLC/MAC/PHY) and a control plane (RRC) protocol terminal to a UE.
  • the gNBs are interconnected through an Xn interface.
  • the gNB is connected to an NGC through a NG interface. More particularly, the gNB is connected to an access and mobility management function through an N2 interface and to a user plane function (UPF) through an N3 interface.
  • UPF user plane function
  • a UE receives information from a base station in downlink (DL) and transmits information to the base station in uplink (UL).
  • the information transmitted and received between the UE and base station includes general data information and various types of control information. There are many physical channels depending on the types/usages of information transmitted and received between the UE and base station.
  • FIG. 3 illustrates physical channels and a general signal transmission method using the physical channels applicable to implementations of the present disclosure.
  • the UE When a UE is powered on or enters anew cell, the UE performs initial cell search (S 11 ).
  • the initial cell search involves acquisition of synchronization to a base station. Specifically, the UE synchronizes its timing with the base station and obtains information such as a cell Identifier (ID) by receiving a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH) from the base station.
  • ID cell Identifier
  • P-SCH primary synchronization channel
  • S-SCH secondary synchronization channel
  • the UE may obtain information broadcast in the cell by receiving a physical broadcast channel (PBCH) from the base station.
  • PBCH physical broadcast channel
  • the UE may monitor the state of a DL channel by receiving a downlink reference signal (DL RS).
  • DL RS downlink reference signal
  • the UE may obtain more detailed system information by receiving a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH), which depends on information in the PDCCH (S 12 ).
  • a physical downlink control channel (PDCCH)
  • a physical downlink shared channel (PDSCH)
  • the UE may perform a random access procedure (S 13 to S 16 ).
  • the UE may transmit a preamble over a physical random access channel (PRACH) (S 13 ) and receive a random access response (RAR) for the preamble over the PDCCH and the PDSCH associated therewith (S 14 ).
  • the UE may transmit a physical uplink shared channel (PUSCH) based on scheduling information in the RAR (S 15 ).
  • the UE may perform a contention resolution procedure by receiving a PDCCH signal and a PDSCH signal associated therewith (S 16 ).
  • the UE may perform reception of a PDCCH signal and/or a PDSCH signal (S 17 ) and transmission of a physical uplink control channel (PUCCH) signal and a PUSCH signal (S 18 ) as a general UL/DL signal transmission procedure.
  • a PDCCH signal and/or a PDSCH signal S 17
  • a physical uplink control channel PUCCH
  • PUSCH PUSCH
  • the UCI includes a hybrid automatic repeat and request acknowledgement/negative acknowledgement (HARQ-ACK/NACK), a scheduling request (SR), a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), etc.
  • HARQ-ACK/NACK hybrid automatic repeat and request acknowledgement/negative acknowledgement
  • SR scheduling request
  • CQI channel quality indicator
  • PMI precoding matrix indicator
  • RI rank indicator
  • the UCI may be periodically transmitted over the PUCCH.
  • the UCI may be transmitted on the PUSCH (if control information and traffic data need to be transmitted simultaneously).
  • a UE may aperiodically transmit the UCI over the PUSCH.
  • FIG. 4 is a diagram illustrating the structure of a radio frame in the LTE system to which implementations of the present disclosure are applicable.
  • the LTE system supports frame structure type 1 for frequency division duplex (FDD), frame structure type 2 for time division duplex (TDD), and frame structure type 3 for an unlicensed cell (UCell).
  • FDD frequency division duplex
  • TDD time division duplex
  • UCD unlicensed cell
  • SCells secondary cells
  • PCell primary cell
  • time resources e.g., a subframe, a slot, a subslot, etc.
  • TU time unit
  • FIG. 4 ( a ) illustrates frame structure type 1.
  • Frame structure type 1 is applicable to both a full-duplex FDD system and a half-duplex FDD system.
  • a DL radio frame is defined as 10 1-ms subframes.
  • a subframe includes 12 or 14 symbols depending on cyclic prefixes (CPs). In the case of a normal CP, a subframe includes 14 symbols, and in the case of an extended CP, a subframe includes 12 symbols.
  • CPs cyclic prefixes
  • a symbol may refer to an OFDM(A) symbol or an SC-FDM(A) symbol.
  • a symbol may refer to an OFDM(A) symbol in DL and an SC-FDM(A) symbol in UL.
  • An OFDM(A) symbol may be referred to as a cyclic prefix-OFDMA(A) (CP-OFDM(A)) symbol
  • an SC-FMD(A) symbol may be referred to as a discrete Fourier transform-spread-OFDM(A) (DFT-s-OFDM(A)) symbol.
  • One subframe may be defined as one or more slots according to a subcarrier spacing (SCS) as follows.
  • SCS subcarrier spacing
  • Table 1 shows subslot configurations in one subframe (normal CP).
  • FIG. 4 ( b ) illustrates frame structure type 2.
  • Frame structure type 2 is applied to a TDD system.
  • Frame structure type 2 includes two half frames.
  • a half frame includes 4 (or 5) normal subframes and 1 (or 0) special subframe.
  • a normal subframe is used for UL or DL according to a UL-DL configuration.
  • a subframe includes two slots.
  • Table 2 shows subframe configurations in a radio frame depending on UL-DL configurations.
  • D denotes a DL subframe
  • U denotes a UL subframe
  • S denotes a special subframe.
  • a special subframe includes a downlink pilot time slot (DwPTS), a guard period (GP), and an uplink pilot time slot (UpPTS).
  • the DwPTS is used for initial cell search, synchronization, or channel estimation at a UE.
  • the UpPTS is used for channel estimation at a base station and UL transmission synchronization acquisition at a UE.
  • the GP is a period for cancelling UL interference caused by multipath delay of a DL signal between DL and UL.
  • Table 3 shows special subframe configurations.
  • X is configured by higher layer signaling (e.g., radio resource control (RRC) signaling) or given as 0.
  • RRC radio resource control
  • FIG. 5 is a diagram illustrating the structure of a slot in the LTE system to which implementations of the present disclosure are applicable.
  • one slot includes a plurality of OFDM symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain.
  • a symbol may refer to a symbol duration.
  • a slot structure may be represented by a resource grid including N DL/UL RB ⁇ N RB sc subcarriers and N DL/UL symb symbols.
  • N DL RB denotes the number of RBs in a DL slot
  • N UL RB denotes the number of RBs in a UL slot.
  • N DL RB and N UL RB are dependent on a DL bandwidth and a UL bandwidth, respectively.
  • N DL symb denotes the number of symbols in a DL slot
  • N UL symb denotes the number of symbols in a UL slot
  • N RB sc denotes the number of subcarriers in one RB.
  • the number of symbols in a slot may vary depending on SCSs and CP lengths (see Table 1). For example, one slot includes 7 symbols in the case of a normal CP case, but includes 6 symbols in the case of an extended CP.
  • An RB is defined as N DL/UL symb (e.g., 7) consecutive symbols in the time domain and N RB sc (e.g., 12) consecutive subcarriers in the frequency domain.
  • the RB may be a physical resource block (PRB) or a virtual resource block (VRB), and PRBs may be mapped to VRBs in a one-to-one correspondence.
  • Two RBs each located in one of the two slots of a subframe may be referred to as an RB pair.
  • the two RBs in the RB pair may have the same RB number (or RB index).
  • a resource consisting of one symbol and one subcarrier is referred to as a resource element (RE) or tone.
  • RE resource element
  • Each RE in the resource grid may be uniquely identified by an index pair (k, 1) in a slot, where k is a frequency-domain index from 0 to N DL/UL RB ⁇ N RB sc ⁇ 1 and 1 is a time-domain index from 0 to N DL/UL symb ⁇ 1.
  • FIG. 6 is a diagram illustrating the structure of a DL subframe in the LTE system to which implementations of the present disclosure are applicable.
  • up to three (or four) OFDM(A) symbols at the beginning of the first slot of a subframe corresponds to a control region to which a DL control channel is allocated.
  • the remaining OFDM(A) symbols correspond to a data region to which a PDSCH is allocated, and a basic resource unit of the data region is an RB.
  • the DL control channel include a physical control format indicator channel (PCFICH), a PDCCH, a physical hybrid-ARQ indicator channel (PHICH), etc.
  • the PCFICH is transmitted in the first OFDM symbol of a subframe, carrying information about the number of OFDM symbols (i.e., the size of a control region) used for transmission of control channels in the subframe.
  • the PHICH is a response channel for UL transmission, carrying a HARQ-ACK/NACK signal.
  • Control information transmitted over the PDCCH is called downlink control information (DCI).
  • the DCI includes UL resource allocation information, DL resource control information, or a UL transmit (TX) power control command for any UE group.
  • FIG. 7 is a diagram illustrating the structure of a UL subframe in the LTE system to which implementations of the present disclosure are applicable.
  • one subframe 600 includes two 0.5-ms slots 601 .
  • Each slot includes a plurality of symbols 602 , each corresponding to one SC-FDMA symbol.
  • An RB 603 is a resource allocation unit, which is defined by 12 subcarriers in the frequency domain and one slot in the time domain.
  • a UL subframe is largely divided into a data region 604 and a control region 605 .
  • the data region refers to communication resources used by each UE to transmit data such as voice, packets, etc. and includes a PUSCH.
  • the control region refers to communication resources used by each UE to transmit a UL control signal, for example, a report on DL channel quality, an ACK/NACK for DL signal reception, a UL scheduling request, etc. and includes a PUCCH.
  • a sounding reference signal (SRS) is transmitted in the last SC-FDMA symbol of a subframe in the time domain.
  • FIG. 8 is a diagram illustrating the structure of a radio frame in the NR system to which implementations of the present disclosure are applicable.
  • One radio frame has a duration of 10 ms, defined as two 5-ms half-frames.
  • One half-frame is defined as five 1-ms subframes.
  • One subframe is divided into one or more slots, and the number of slots in a subframe depends on SCSs.
  • Each slot includes 12 or 14 OFDM(A) symbols depending on CPs.
  • Each slot includes 14 symbols in the case of a normal CP and 12 symbols in the case of an extended CP.
  • a symbol may include an OFDM symbol (or CP-OFDM symbol), and/or SC-FDMA symbol (or DFT-s-OFDM symbol).
  • Table 4 shows the number of symbols in each slot, the number of slots in each frame, and the number of slots in each subframe depending on SCSs in the case of the normal CP.
  • Table 5 shows the number of symbols in each slot, the number of slots in each frame, and the number of slots in each subframe depending on SCSs in the case of the extended CP,
  • N slot symb denotes the number of symbols in a slot
  • N frame denotes the number of slots in a frame
  • N subframe denotes the number of slots in a subframe
  • different OFDM(A) numerologies may be configured for a plurality of cells aggregated for one UE. Therefore, the (absolute) duration of a time resource (e.g., SF, slot, or TTI) including the same number of symbols may differ between the aggregated cells (such a time resource is referred to as a TU for convenience of description).
  • a time resource e.g., SF, slot, or TTI
  • FIG. 9 is a diagram illustrating the structure of a slot in the NR system to which implementations of the present disclosure are applicable.
  • One slot includes a plurality of symbols in the time domain. For example, one slot includes 7 symbols in the case of a normal CP and 6 symbols in the case of an extended CP.
  • a carrier includes a plurality of subcarriers in the frequency domain.
  • An RB is defined as a plurality of (e.g., 12) consecutive subcarriers in the frequency domain.
  • a bandwidth part is defined as a plurality of consecutive (P)RBs in the frequency domain.
  • the BWP may correspond to one numerology (e.g., SCS, CP length, etc.).
  • a carrier may include up to N (e.g., 5) BWPs. Data communication may be conducted in an active BWP, and only one BWP may be activated for one UE. Each element in a resource grid is referred to as an RE. One complex symbol may be mapped to the RE.
  • FIG. 10 is a diagram illustrating the structure of a self-contained slot in the NR system to which implementations of the present disclosure are applicable.
  • a base station and a UE may sequentially perform DL transmission and UL transmission in one slot. That is, the base station and UE may exchange not only DL data but also a UL ACK/NACK for the DL data in the one slot. Consequently, this structure may reduce a time required until data retransmission when a data transmission error occurs, thereby minimizing the latency of final data transfer.
  • a time gap with a predetermined time duration is required to allow the base station and UE to switch from transmission mode to reception mode and vice versa.
  • some OFDM symbols at the time of switching from DL to UL may be set to a GP in the self-contained slot structure.
  • the self-contained slot structure includes both DL and UL control regions
  • these control regions may be selectively included in the self-contained slot structure.
  • the self-contained slot structure according to the present disclosure may include either the DL control region or UL control region as well as both the DL and UL control regions as illustrated in FIG. 10 .
  • one slot may be configured in the following order: DL control region/DL data region/UL control region/UL data region or UL control region/UL data region/DL control region/DL data region.
  • a PDCCH may be transmitted in the DL control region, and a PDSCH may be transmitted in the DL data region.
  • a PUCCH may be transmitted in the UL control region, and a PUSCH may be transmitted in the UL data region.
  • the PDCCH may carry DCI, for example, DL data scheduling information, UL data scheduling information, etc.
  • the PUCCH may carry UCI, for example, an ACK/NACK for DL data, channel state information (CSI), an SR, etc.
  • CSI channel state information
  • the PDSCH may carry DL data (e.g., DL-shared channel transport block (DL-SCH TB)).
  • a modulation scheme such as quadrature phase shift keying (QPSK), 16-ary quadrature amplitude modulation (16QAM), 64QAM, or 256QAM.
  • QPSK quadrature phase shift keying
  • 16QAM 16-ary quadrature amplitude modulation
  • 64QAM 64QAM
  • 256QAM 256QAM.
  • a TB is encoded into a codeword.
  • the PDSCH may carry up to two codewords. Scrambling and modulation mapping are performed on a codeword basis, and modulation symbols generated from each codeword are mapped to one or more layers (layer mapping). Each layer is mapped to resources together with a demodulation reference signal (DMRS), created as an OFDM symbol signal, and then transmitted through a corresponding antenna port.
  • DMRS demodulation reference signal
  • the PDCCH may carry DCI, and the QPSK modulation scheme is applied thereto.
  • One PDCCH includes 1, 2, 4, 8, or 16 control channel elements (CCEs) depending on aggregation levels (ALs).
  • One CCE includes 6 resource element groups (REGs).
  • One REG is defined as one OFDM symbol and one (P)RB.
  • the Machine Type Communication refers to communication technology adopted by 3 rd Generation Partnership Project (3GPP) to meet Internet of Things (IoT) service requirements. Since the MTC does not require high throughput, it may be used as an application for machine-to-machine (M2M) and Internet of Things (IoT).
  • 3GPP 3 rd Generation Partnership Project
  • IoT Internet of Things
  • the MTC may be implemented to satisfy the following requirements: (i) low cost and low complexity; (ii) enhanced coverage; and (iii) low power consumption.
  • the MTC was introduced in 3GPP release 10.
  • the MTC features added in each 3GPP release will be described.
  • the MTC load control was introduced in 3GPP releases 10 and 11.
  • the load control method prevents IoT (or M2M) devices from creating a heavy load on the base station suddenly.
  • the base station may disconnect connections with IoT devices to control the load.
  • the base station may prevent the UE from attempting to establish a connection by informing the UE that access will become available through broadcasting such as SIB14.
  • the UE category indicates the amount of data that the UE is capable of processing using a communication modem.
  • a UE that belongs to UE category 0 may use a reduced peak data rate, a half-duplex operation with relaxed RF requirements, and a single reception antenna, thereby reducing the baseband and RF complexity of the UE.
  • enhanced MTC enhanced MTC
  • the UE operates in a bandwidth of 1.08 MHz, which is the minimum frequency bandwidth supported by legacy LTE, thereby further reducing the cost and power consumption.
  • MTC Mobility Management Entity
  • the MTC may be referred to as another terminology such as ‘eMTC’, ‘LTE-M1/M2’, ‘bandwidth reduced low complexity/coverage enhanced (BL/CE)’, ‘non-BL UE (in enhanced coverage)’, ‘NR MTC’, or ‘enhanced BL/CE’.
  • MTC may be replaced with a term defined in the future 3GPP standards.
  • the MTC operates only in a specific system bandwidth (or channel bandwidth).
  • the specific system bandwidth may use 6 RBs of the legacy LTE as shown in Table 6 below and defined by considering the frequency range and subcarrier spacing (SCS) shown in Tables 7 to 9.
  • the specific system bandwidth may be referred to as narrowband (NB).
  • the legacy LTE may encompass the contents described in the 3GPP standards expect the MTC.
  • the MTC may use RBs corresponding the smallest system bandwidth in Tables 8 and 9 as in the legacy LTE.
  • the MTC may operate in at least one BWP or in a specific band of a BWP.
  • Table 7 shows the frequency ranges (FRs) defined for the NR.
  • Table 8 shows the maximum transmission bandwidth configuration (NRB) for the channel bandwidth and SCS in NR FR1.
  • Table 9 shows the maximum transmission bandwidth configuration (NRB) for the channel bandwidth and SCS in NR FR2.
  • the MTC follows narrowband operation to transmit and receive physical channels and signals, and the maximum channel bandwidth is reduced to 1.08 MHz or 6 (LTE) RBs.
  • the narrowband may be used as a reference unit for allocating resources to some downlink and uplink channels, and the physical location of each narrowband in the frequency domain may vary depending on the system bandwidth.
  • the 1.08 MHz bandwidth for the MTC is defined to allow an MTC UE to follow the same cell search and random access procedures as those of the legacy UE.
  • the MTC may be supported by a cell with a much larger bandwidth (e.g., 10 MHz), but the physical channels and signals transmitted/received in the MTC are always limited to 1.08 MHz.
  • the larger bandwidth may be supported by the legacy LTE system, NR system, 5G system, etc.
  • the narrowband is defined as 6 non-overlapping consecutive physical RBs in the frequency domain.
  • FIG. 11 illustrates examples of narrowband operations and frequency diversity.
  • FIG. 11 ( a ) illustrates an example of the narrowband operation
  • FIG. 11 ( b ) illustrates an example of repetitions with RF retuning.
  • the MTC supports limited frequency, spatial, and time diversity due to the narrowband RF, single antenna, and limited mobility. To reduce the effects of fading and outages, frequency hopping is supported between different narrowbands by the RF retuning.
  • the frequency hopping is applied to different uplink and downlink physical channels when repetition is enabled.
  • the first 16 subframes may be transmitted on the first narrowband.
  • the RF front-end is retuned to another narrowband, and the remaining 16 subframes are transmitted on the second narrowband.
  • the MTC narrowband may be configured by system information or DCI.
  • the MTC operates in half-duplex mode and uses limited (or reduced) maximum transmission power.
  • the MTC does not use a channel (defined in the legacy LTE or NR) that should be distributed over the full system bandwidth of the legacy LTE or NR.
  • the MTC does not use the following legacy LTE channels: PCFICH, PHICH, and PDCCH.
  • an MTC PDCCH (MPDCCH)
  • MPDCCH MTC PDCCH
  • the MPDCCH may occupy a maximum of 6 RBs in the frequency domain and one subframe in the time domain.
  • the MPDCCH is similar to an evolved PDCCH (EPDCCH) and supports a common search space for paging and random access.
  • EPDCCH evolved PDCCH
  • the concept of the MPDCCH is similar to that of the EPDCCH used in the legacy LTE.
  • the MTC uses newly defined DCI formats.
  • DCI formats 6-0A, 6-0B, 6-1A, 6-1B, 6-2, etc. may be used.
  • a physical broadcast channel (PBCH), physical random access channel (PRACH), MPDCCH, PDSCH, PUCCH, and PUSCH may be repeatedly transmitted.
  • the MTC repeated transmission enables decoding of an MTC channel in a poor environment such as a basement, that is, when the signal quality or power is low, thereby increasing the radius of a cell or supporting the signal propagation effect.
  • the MTC may support a limited number of transmission modes (TMs), which are capable of operating on a single layer (or single antenna), or support a channel or reference signal (RS), which are capable of operating on a single layer.
  • TMs transmission modes
  • RS channel or reference signal
  • the MTC may operate in TM 1, 2, 6, or 9.
  • HARQ retransmission is adaptive and asynchronous and performed based on a new scheduling assignment received on the MPDCCH.
  • PDSCH scheduling (DCI) and PDSCH transmission occur in different subframes (cross-subframe scheduling).
  • All resource allocation information (e.g., a subframe, a transport block size (TBS), a subband index, etc.) for SIB1 decoding is determined by a master information block (MIB) parameter (in the MTC, no control channel is used for the SIB1 decoding).
  • MIB master information block
  • All resource allocation information (e.g., a subframe, a TBS, a subband index, etc.) for SIB2 decoding is determined by several SIB1 parameters (in the MTC, no control channel is used for the SIB2 decoding).
  • the MTC supports an extended discontinuous reception (DRX) cycle.
  • DRX discontinuous reception
  • the MTC may use the same primary synchronization signal/secondary synchronization signal/common reference signal (PSS/SSS/CRS) as that used in the legacy LTE or NR.
  • PSS/SSS/CRS primary synchronization signal/secondary synchronization signal/common reference signal
  • the PSS/SSS is transmitted in the unit of SS block (or SS/PBCH block or SSB), and a tracking RS (TRS) may be used for the same purpose as the CRS. That is, the TRS is a cell-specific RS and may be used for frequency/time tracking.
  • MTC operation modes and levels will be described.
  • the MTC may be divided into two operation modes (first and second modes) and four different levels as shown in Table 10 below.
  • the MTC operation mode may be referred to CE mode.
  • the first and second modes may be referred to CE mode A and CE mode B, respectively.
  • the first mode is defined for small coverage where full mobility and channel state information (CSI) feedback are supported. In the first mode, the number of repetitions is zero or small. The operation in the first mode may have the same operation coverage as that of UE category 1.
  • the second mode is defined for a UE with a very poor coverage condition where CSI feedback and limited mobility are supported. In the second mode, the number of times that transmission is repeated is large. The second mode provides up to 15 dB coverage enhancement with reference to the coverage of UE category 1.
  • Each level of the MTC is defined differently in RACH and paging procedures.
  • the MTC operation mode is determined by the base station, and each level is determined by the MTC UE. Specifically, the base station transmits RRC signaling including information for the MTC operation mode to the UE.
  • the RRC signaling may include an RRC connection setup message, an RRC connection reconfiguration message, or an RRC connection reestablishment message.
  • the term “message” may refer to an information element (IE).
  • the MTC UE determines a level within the operation mode and transmits the determined level to the base station. Specifically, the MTC UE determines the level within the operation mode based on measured channel quality (e.g., RSRP, RSRQ, SINR, etc.) and informs the base station of the determined level using a PRACH resource (e.g., frequency, time, preamble, etc.).
  • measured channel quality e.g., RSRP, RSRQ, SINR, etc.
  • a PRACH resource e.g., frequency, time, preamble, etc.
  • the MTC operates in the narrowband.
  • the location of the narrowband may vary in each specific time unit (e.g., subframe or slot).
  • the MTC UE tunes to a different frequency in every time unit.
  • all frequency retuning may require a certain period of time.
  • the guard period is required for transition from one time unit to the next time unit, and no transmission and reception occurs during the corresponding period.
  • the guard period varies depending on whether the current link is downlink or uplink and also varies depending on the state thereof.
  • An uplink guard period i.e., guard period defined for uplink
  • a first downlink narrowband center frequency is different from a second narrowband center frequency
  • a first uplink narrowband center frequency is different from a second downlink center frequency.
  • the MTC guard period defined in the legacy LTE will be described.
  • a guard period consisting of at most N symb retune SC-FDMA symbols is created for Tx-Tx frequency retuning between two consecutive subframes.
  • N symb retune is equal to ce-RetuningSymbols. Otherwise, N symb retune is 2.
  • a guard period consisting of SC-FDMA symbols is created for Tx-Tx frequency retuning between a first special subframe and a second uplink subframe for frame structure type 2.
  • FIG. 12 illustrates physical channels available in MTC and a general signal transmission method using the same.
  • the MTC UE When an MTC UE is powered on or enters a new cell, the MTC UE performs initial cell search in step S 1201 .
  • the initial cell search involves acquisition of synchronization with a base station. Specifically, the MTC UE synchronizes with the base station by receiving a primary synchronization signal (PSS) and a second synchronization signal (SSS) from the base station and obtains information such as a cell identifier (ID).
  • PSS/SSS used by the MTC UE for the initial cell search may be equal to a PSS/SSS or a resynchronization signal (RSS) of the legacy LTE.
  • the MTC UE may acquire broadcast information in the cell by receiving a PBCH signal from the base station.
  • the MTC UE may monitor the state of a downlink channel by receiving a downlink reference signal (DL RS).
  • DL RS downlink reference signal
  • the broadcast information transmitted on the PBCH corresponds to the MIB.
  • the MIB is repeated in the first slot of subframe #0 of a radio frame and other subframes (subframe #9 in FDD and subframe #5 in the TDD).
  • the PBCH repetition is performed such that the same constellation point is repeated on different OFDM symbols to estimate an initial frequency error before attempting PBCH decoding.
  • FIG. 13 illustrates an example of system information transmissions in MTC.
  • FIG. 13 ( a ) illustrates an example of a repetition pattern for subframe #0 in FDD and a frequency error estimation method for a normal CP and repeated symbols
  • FIG. 13 ( b ) illustrates an example of transmission of an SIB-BR on a wideband LTE channel.
  • SIB1-BR bandwidth reduced device
  • the SIB-BR is transmitted on a PDSCH directly without any related control channels.
  • the SIB-BR is maintained without change for 512 radio frames (5120 ms) to allow a large number of subframes to be combined.
  • Table 11 shows an example of the MIB.
  • MasterInformationBlock SEQUENCE ⁇ d1-Bandwidth ENUMERATED ⁇ n6, n15, n25, n50, n75, n100 ⁇ , phich-Config PHICH-Config, systemFrameNumber BIT STRING (SIZE (8)), schedulingInfoSIB1-BR-r13 INTEGER (0 . . . 31), systemInfoUnchanged-BR-r15 BOOLEAN, spare BIT STRING (SIZE (4)) ⁇ --ASN1STOP
  • the schedulingInfoSIB1-BR field indicates the index of a table that defines SystemInformationBlockType1-BR scheduling information.
  • the zero value means that SystemInformationBlockType1-BR is not scheduled.
  • the overall function and information carried by SystemInformationBlockType1-BR (or SIB1-BR) is similar to SIB1 of the legacy LTE.
  • the contents of SIB1-BR may be categorized as follows: (1) PLMN; (2) cell selection criteria; and (3) scheduling information for SIB2 and other SIBs.
  • the MTC UE may acquire more detailed system information by receiving a MPDCCH and a PDSCH based on information in the MPDCCH in step S 1202 .
  • the MPDCCH has the following features: (1) The MPDCCH is very similar to the EPDCCH; (2) The MPDCCH may be transmitted once or repeatedly (the number of repetitions is configured through higher layer signaling); (3) Multiple MPDCCHs are supported and a set of MPDCCHs are monitored by the UE; (4) the MPDCCH is generated by combining enhanced control channel elements (eCCEs), and each CCE includes a set of REs; and (5) the MPDCCH supports an RA-RNTI, SI-RNTI, P-RNTI, C-RNTI, temporary C-RNTI, and semi-persistent scheduling (SPS) C-RNTI.
  • SPS semi-persistent scheduling
  • SIB2 includes parameters related to paging.
  • a paging occasion (PO) is a subframe in which the P-RNTI is capable of being transmitted on the MPDCCH.
  • the PO may refer to a subframe where MPDCCH repetition is started.
  • a paging frame (PF) is one radio frame, which may contain one or multiple POs.
  • DRX is used, the MTC UE monitors one PO per DRX cycle.
  • a paging narrowband (PNB) is one narrowband, on which the MTC UE performs paging message reception.
  • the MTC UE may transmit a preamble on a PRACH (S 1203 ) and receive a response message (e.g., random access response (RAR)) for the preamble on the MPDCCH and the PDSCH related thereto (S 1204 ).
  • MTC UE may perform a contention resolution procedure including transmission of an PUSCH (Physical Uplink Shared Channel) using scheduling information in the RAR (S 1205 ) and reception of a MPDCCH signal and a PDSCH signal related thereto (S 1206 ).
  • PUSCH Physical Uplink Shared Channel
  • the signals and messages (e.g., Msg 1, Msg 2, Msg 3, and Msg 4) transmitted during the RACH procedure may be repeatedly transmitted, and a repetition pattern may be configured differently depending on coverage enhancement (CE) levels.
  • Msg 1 may represent the PRACH preamble
  • Msg 2 may represent the RAR
  • Msg 3 may represent uplink transmission for the RAR at the MTC UE
  • Msg 4 may represent downlink transmission for Msg 3 from the base station.
  • PRACH resource For random access, signaling of different PRACH resources and different CE levels is supported. This provides the same control of the near-far effect for the PRACH by grouping UEs that experience similar path loss together. Up to four different PRACH resources may be signaled to the MTC UE.
  • the MTC UE measures RSRP using a downlink RS (e.g., CRS, CSI-RS, TRS, etc.) and selects one of random access resources based on the measurement result.
  • a downlink RS e.g., CRS, CSI-RS, TRS, etc.
  • Each of four random access resources has an associated number of PRACH repetitions and an associated number of RAR repetitions.
  • the MTC UE in poor coverage requires a large number of repetitions so as to be detected by the base station successfully and needs to receive as many RARs as the number of repetitions such that the coverage levels thereof are satisfied.
  • the search spaces for RAR and contention resolution messages are defined in the system information, and the search space is independent for each coverage level.
  • a PRACH waveform used in the MTC is the same as that in the legacy LTE (for example, OFDM and Zadoff-Chu sequences).
  • the MTC UE may perform reception of an MPDCCH signal and/or a PDSCH signal (S 1207 ) and transmission of a PUSCH signal and/or a PUCCH signal (S 1208 ) as a normal uplink/downlink signal transmission procedure.
  • Control information that the MTC UE transmits to the base station is commonly referred to as uplink control information (UCI).
  • the UCI includes a HARQ-ACK/NACK, scheduling request, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), etc.
  • the MTC UE When the MTC UE has established an RRC connection, the MTC UE blindly decodes the MPDCCH in a configured search space to obtain uplink and downlink data assignments.
  • the MTC In the MTC, all available OFDM symbols in a subframe are used to transmit DCI. Accordingly, time-domain multiplexing is not allowed between control and data channels in the subframe. Thus, the cross-subframe scheduling may be performed between the control and data channels as described above.
  • the MPDCCH schedules a PDSCH assignment in subframe #N+2.
  • DCI carried by the MPDCCH provides information for how many times the MPDCCH is repeated so that the MTC UE may know the number of repetitions when PDSCH transmission is started.
  • the PDSCH assignment may be performed on different narrowbands.
  • the MTC UE may need to perform retuning before decoding the PDSCH assignment.
  • scheduling follows the same timing as that of the legacy LTE.
  • the last MPDCCH in subframe #N schedules PUSCH transmission starting in subframe #N+4.
  • FIG. 14 illustrates an example of scheduling for each of MTC and legacy LTE.
  • a legacy LTE assignment is scheduled using the PDCCH and uses the initial OFDM symbols in each subframe.
  • the PDSCH is scheduled in the same subframe in which the PDCCH is received.
  • the MTC PDSCH is cross-subframe scheduled, and one subframe is defined between the MPDCCH and PDSCH to allow MPDCCH decoding and RF retuning.
  • MTC control and data channels may be repeated for a large number of subframes to be decoded in an extreme coverage condition. Specifically, the MTC control and data channels may be repeated for a maximum of 256 subframes for the MPDCCH and a maximum of 2048 subframes for the PDSCH
  • Narrowband-Internet of Things (NB-IoT)
  • the NB-IoT may refer to a system for providing low complexity and low power consumption based on a system bandwidth (BW) corresponding to one physical resource block (PRB) of a wireless communication system (e.g., LTE system, NR system, etc.).
  • BW system bandwidth
  • PRB physical resource block
  • the NB-IoT may be referred to as another terminology such as ‘NB-LTE’, ‘NB-IoT enhancement’, ‘further enhanced NB-IoT’, or ‘NB-NR’.
  • the NB-IoT may be replaced with a term defined or to be defined in the 3GPP standards. For convenience of description, all types of NB-IoT is commonly referred to as ‘NB-IoT’.
  • the NB-IoT may be used to implement the IoT by supporting an MTC device (or MTC UE) in a cellular system. Since one PRB of the system BW is allocated for the NB-IoT, frequency may be efficiently used. In addition, considering that in the NB-IoT, each UE recognizes a single PRB as one carrier, the PRB and carrier described herein may be considered to have the same meaning.
  • the present disclosure describes frame structures, physical channels, multi-carrier operation, operation modes, and general signal transmission and reception of the NB-IoT based on the LTE system, it is apparent that the present disclosure is applicable to the next-generation systems (e.g., NR system, etc.).
  • the details of the NB-IoT described in this document may be applied to the MTC, which has similar purposes (e.g., low power, low cost, coverage enhancement, etc.).
  • the NB-IoT frame structure may vary depending on SCSs.
  • FIGS. 15 and 16 illustrate examples of NB-IoT frame structures depending on SCSs. Specifically, FIG. 15 illustrates a frame structure with an SCS of 15 kHz, and FIG. 16 illustrates a frame structure with an SCS of 3.75 kHz.
  • the NB-IoT frame structure is not limited thereto, and different SCSs (e.g., 30 kHz, etc.) may be applied to NB-IoT by changing the time/frequency unit.
  • the present disclosure describes the NB-IoT frame structure based on the LTE frame structure, this is merely for convenience of description, and the present disclosure is not limited thereto. That is, the methods proposed in the present disclosure are applicable to NB-IoT, which is based on frame structures of next-generation systems (e.g., NR system).
  • next-generation systems e.g., NR system
  • the NB-IoT frame structure for the 15 kHz SCS may be the same as that of the legacy system (LTE system).
  • a 10-ms NB-IoT frame may include 10 1-ms NB-IoT subframes, and the 1-ms NB-IoT subframe may include two NB-IoT slots, each having a duration of 0.5 ms.
  • Each 0.5-ms NB-IoT slot ms may include 7 OFDM symbols.
  • a 10-ms NB-IoT frame may include five 2-ms NB-IoT subframes, and the 2-ms NB-IoT subframe may include 7 OFDM symbols and one GP.
  • the 2-ms NB-IoT subframe may be referred to as an NB-IoT slot or an NB-IoT resource unit (RU).
  • RB resource grid of the LTE system illustrated in FIG. 5
  • the NB-IoT uplink physical resource may be configured by limiting to the system bandwidth to one RB as in the NB-IoT downlink.
  • a resource grid for the NB-IoT uplink may be represented as shown in FIG. 17 .
  • the number of subcarriers N sc UL and the slot period T slot may be given in Table 12 below.
  • FIG. 17 illustrates an example of the resource grid for NB-IoT uplink.
  • a resource unit (RU) for the NB-IoT uplink may include SC-FDMA symbols in the time domain and N symb UL N slots UL consecutive subcarriers in the frequency domain.
  • N sc RU and N symb UL may be given in Table 11 below.
  • N sc RU and N symb UL may be given in Table 12.
  • a base station and/or UE that support NB-IoT may be configured to transmit and receive physical channels and signals different from those in the legacy system.
  • the physical channels and/or signals supported in the NB-IoT will be described in detail.
  • the NB-IoT downlink will be described.
  • an OFDMA scheme with the 15 kHz subcarrier spacing may be applied. Accordingly, orthogonality between subcarriers may be provided, thereby supporting coexistence with the legacy system (e.g., LTE system, NR system, etc.).
  • the legacy system e.g., LTE system, NR system, etc.
  • N ‘narrowband’ may be added.
  • DL physical channels may be defined as follows: ‘narrowband physical broadcast channel (NPBCH)’, ‘narrowband physical downlink control channel (NPDCCH)’, ‘narrowband physical downlink shared channel (NPDSCH)’, etc.
  • DL physical signals may be defined as follows: ‘narrowband primary synchronization signal (NPSS)’, ‘narrowband secondary synchronization signal (NSSS)’, ‘narrowband reference signal (NRS)’, ‘narrowband positioning reference signal (NPRS)’, ‘narrowband wake-up signal (NWUS)’, etc.
  • the above-described downlink physical channels and physical signals for the NB-IoT may be configured to be transmitted based on time-domain multiplexing and/or frequency-domain multiplexing.
  • the NPBCH, NPDCCH, and NPDSCH which are downlink channels of the NB-IoT system, may be repeatedly transmitted for coverage enhancement.
  • the NB-IoT uses newly defined DCI formats.
  • the DCI formats for the NB-IoT may be defined as follows: DCI format N0, DCI format N1, DCI format N2, etc.
  • the NB-IoT uplink may support multi-tone and single-tone transmissions.
  • the multi-tone transmission may support the 15 kHz subcarrier spacing
  • the single-tone transmission may support both the 15 kHz and 3.75 kHz subcarrier spacing.
  • N may also be added to distinguish the physical channels of the NB-IoT system from those of the legacy system, similarly to the NB-IoT downlink.
  • uplink physical channels may be defined as follows: ‘narrowband physical random access channel (NPRACH)’, ‘narrowband physical uplink shared channel (NPUSCH)’, etc.
  • UL physical signals may be defined as follows: ‘narrowband demodulation reference signal (NDMRS)’.
  • the NPUSCH may be configured with NPUSCH format 1 and NPUSCH format 2.
  • NPUSCH format 1 is used for UL-SCH transmission (or transfer)
  • NPUSCH format 2 may be used for UCI transmission such as HARQ ACK signaling.
  • the NPRACH which is a downlink channel of the NB-IoT system, may be repeatedly transmitted for coverage enhancement.
  • frequency hopping may be applied to the repeated transmission.
  • the multi-carrier operation in the NB-IoT may mean that when the base station and/or UE uses different usage of multiple carriers (i.e., different types of multiple carriers) in transmitting and receiving a channel and/or a signal in the NB-IoT.
  • multiple carriers i.e., different types of multiple carriers
  • NB-IoT may operate in multi-carrier mode as described above.
  • NB-IoT carriers may be divided into an anchor type carrier (i.e., anchor carrier or anchor PRB) and a non-anchor type carrier (i.e., non-anchor carrier or non-anchor PRB).
  • anchor type carrier i.e., anchor carrier or anchor PRB
  • non-anchor type carrier i.e., non-anchor carrier or non-anchor PRB
  • the anchor carrier may mean a carrier for transmitting the NPDSCH that carries the NPSS, NSSS, NPBCH, and SIB (N-SIB) for initial access.
  • the carrier for initial access may be referred to as the anchor carrier, and the remaining carrier(s) may be referred to as the non-anchor carrier.
  • the operation mode of the NB-IoT will be described.
  • the NB-IoT system may support three operation modes.
  • FIG. 18 illustrates an example of operation modes supported in the NB-IoT system.
  • the present disclosure describes the NB-IoT operation mode based on the LTE band, this is merely for convenience of description and the present disclosure is also applicable to other system bands (e.g., NR system band).
  • FIG. 18 ( a ) illustrates an in-band system
  • FIG. 18 ( b ) illustrates a guard-band system
  • FIG. 18 ( c ) illustrates a stand-alone system.
  • the in-band system, guard-band system, and stand-alone system may be referred to as in-band mode, guard-band mode, and stand-alone mode, respectively.
  • the in-band system may mean a system or mode that uses one specific RB (PRB) in the legacy LTE band for the NB-IoT.
  • PRB specific RB
  • the guard-band system may mean a system or mode that uses a space reserved for the guard band of the legacy LTE band for the NB-IoT.
  • the guard band of the LTE carrier which is not used as the RB in the LTE system may be allocated.
  • the legacy LTE band may be configured such that each LTE band has the guard band of minimum 100 kHz at the end thereof. In order to use 200 kHz, two non-contiguous guard bands may be used.
  • the in-band system and the guard-band system may operate in a structure where the NB-IoT coexists in the legacy LTE band.
  • the stand-alone system may mean a system or mode independent from the legacy LTE band.
  • a frequency band e.g., reallocated GSM carrier
  • GERAN GSM EDGE radio access network
  • the above three operation modes may be applied independently, or two or more operation modes may be combined and applied.
  • FIG. 19 illustrates an example of physical channels available in the NB-IoT and a general signal transmission method using the same.
  • an NB-IoT UE may receive information from a base station in downlink (DL) and transmit information to the base station in uplink (UL).
  • the base station may transmit the information to the NB-IoT UE in downlink and receive the information from the NB-IoT UE in uplink in the wireless communication system.
  • Information transmitted and received between the base station and the NB-IoT UE may include various data and control information, and various physical channels may be used depending on the type/usage of information transmitted and received therebetween.
  • the NB-IoT signal transmission and reception method described with reference to FIG. 19 may be performed by wireless communication devices which will be described later (e.g., devices of FIGS. 32 to 37 ).
  • the NB-IoT UE may perform initial cell search (S 1911 ).
  • the initial cell search involves acquisition of synchronization with the base station. Specifically, the NB-IoT UE may synchronize with the base station by receiving an NPSS and an NSSS from the base station and obtain information such as a cell ID. Thereafter, the NB-IoT UE may acquire information broadcast in the cell by receiving an NPBCH from the base station.
  • the NB-IoT UE may monitor the state of a downlink channel by receiving a downlink reference signal (DL RS).
  • DL RS downlink reference signal
  • the base station may perform the initial cell search, and more particularly, the base station may synchronize with the UE. Specifically, the base station may synchronize with the NB-IoT UE by transmitting the NPSS and NSSS to the UE and transmit the information such as the cell ID. The base station may transmit the broadcast information in the cell by transmitting (or broadcasting) the NPBCH to the NB-IoT UE. The base station may transmit the DL RS to the NB-IoT UE during the initial cell search to check the downlink channel state.
  • the NB-IoT UE may acquire more detailed system information by receiving a NPDCCH and a NPDSCH related to thereto (S 1912 ).
  • the base station may transmit the more detailed system information by transmitting the NPDCCH and the NPDSCH related to thereto to the NB-IoT UE.
  • the NB-IoT UE may perform a random access procedure to complete the access to the base station (S 1913 to S 1916 ).
  • the NB-IoT UE may transmit a preamble on an NPRACH (S 1913 ).
  • the NPRACH may be repeatedly transmitted based on frequency hopping for coverage enhancement.
  • the base station may (repeatedly) receive the preamble from the NB-IoT UE over the NPRACH.
  • the NB-IoT UE may receive a random access response (RAR) for the preamble from the base station on the NPDCCH and the NPDSCH related thereto (S 1914 ). That is, the base station may transmit the random access response (RAR) for the preamble to the base station on the NPDCCH and the NPDSCH related thereto.
  • RAR random access response
  • the NB-IoT UE may transmit an NPUSCH using scheduling information in the RAR (S 1915 ) and perform a contention resolution procedure based on the NPDCCH and the NPDSCH related thereto (S 1916 ). That is, the base station may receive the NPUSCH from the NB-IoT UE based on the scheduling information in the RAR and perform the contention resolution procedure.
  • the NB-IoT UE may perform NPDCCH/NPDSCH reception (S 1917 ) and NPUSCH transmission (S 1918 ) as a normal UL/DL signal transmission procedure.
  • the base station may transmit the NPDCCH/NPDSCH to the NB-IoT UE and receive the NPUSCH from the NB-IoT UE during the normal uplink/downlink signal transmission procedure.
  • the NPBCH, NPDCCH, NPDSCH, etc. may be repeatedly transmitted for the coverage enhancement as described above.
  • UL-SCH (normal uplink data) and UCI may be transmitted on the NPUSCH.
  • the UL-SCH and UCI may be configured to be transmitted in different NPUSCH formats (e.g., NPUSCH format 1, NPUSCH format 2, etc.)
  • the UCI means control information transmitted from the UE to the base station.
  • the UCI may include the HARQ ACK/NACK, scheduling request (SR), CSI, etc.
  • the CSI may include the CQI, PMI, RI, etc.
  • the UCI may be transmitted over the NPUSCH in the NB-IoT as described above.
  • the UE may transmit the UCI on the NPUSCH periodically, aperiodically, or semi-persistently according to the request/indication from the network (e.g., base station).
  • the procedure in which the NB-IoT UE initially accesses the base station is briefly described in the section “General Signal Transmission and Reception Procedure in NB-IoT”. Specifically, the above procedure may be subdivided into a procedure in which the NB-IoT UE searches for an initial cell and a procedure in which the NB-IoT UE obtains system information.
  • FIG. 20 illustrates a particular procedure for signaling between a UE and abase station (e.g., NodeB, eNodeB, eNB, gNB, etc.) for initial access in the NB-IoT.
  • abase station e.g., NodeB, eNodeB, eNB, gNB, etc.
  • a normal initial access procedure, an NPSS/NSSS configuration, and acquisition of system information (e.g., MIB, SIB, etc.) in the NB-IoT will be described with reference to FIG. 20 .
  • FIG. 20 is one example of Initial Access Procedure in NB-IoT.
  • Each physical channel and/or a name of a physical signal may be differently set or referred to according to a wireless communication system to which NB-IoT is applied.
  • NB-IoT based on the LTE system
  • the details of the initial access procedure are also applicable to the MTC.
  • the NB-IoT UE may receive a narrowband synchronization signal (e.g., NPSS, NSSS, etc.) from the base station (S 2010 and S 2020 ).
  • the narrowband synchronization signal may be transmitted through physical layer signaling.
  • the NB-IoT UE may receive a master information block (MIB) (e.g., MIB-NB) from the base station on an NPBCH (S 2030 ).
  • MIB master information block
  • the MIB may be transmitted through higher layer signaling (e.g., RRC signaling).
  • the NB-IoT UE may receive a system information block (SIB) from the base station on an NPDSH (S 2040 and S 2050 ).
  • SIB system information block
  • the NB-IoT UE may receive SIB1-NB, SIB2-NB, etc. on the NPDSCH through the higher layer signaling (e.g., RRC signaling).
  • SIB1-NB may refer to system information with high priority among SIBs
  • SIB2-NB may refer to system information with lower priority than SIB1-NB.
  • the NB-IoT may receive an NRS from the base station (S 2060 ), and this operation may be performed through physical layer signaling.
  • the procedure in which the NB-IoT UE performs random access to the base station is briefly described in the section “General Signal Transmission and Reception Procedure in NB-IoT”. Specifically, the above procedure may be subdivided into a procedure in which the NB-IoT UE transmits a preamble to the base station and a procedure in which the NB-IoT receives a response for the preamble.
  • FIG. 21 illustrates a particular procedure for signaling between a UE and a base station (e.g., NodeB, eNodeB, eNB, gNB, etc.) for random access in the NB-IoT.
  • a base station e.g., NodeB, eNodeB, eNB, gNB, etc.
  • FIG. 21 illustrates a particular procedure for signaling between a UE and a base station (e.g., NodeB, eNodeB, eNB, gNB, etc.) for random access in the NB-IoT.
  • a base station e.g., NodeB, eNodeB, eNB, gNB, etc.
  • messages e.g., msg1, msg2, msg3, msg4 used therefor.
  • FIG. 21 illustrates an example of the random access procedure in the NB-IoT.
  • the name of each physical channel, physical signal, and/or message may vary depending on the wireless communication system to which the NB-IoT is applied.
  • the NB-IoT based on the LTE system is considered in FIG. 22 , this is merely for convenience of description and details thereof are applicable to the NB-IoT based on the NR system.
  • the details of the initial access procedure are also applicable to the MTC.
  • the NB-IoT may be configured to support contention-based random access.
  • the NB-IoT UE may select an NPRACH resource based on the coverage level of the corresponding UE.
  • the NB-IoT UE may transmit a random access preamble (i.e., message 1, msg1) to the base station on the selected NPRACH resource.
  • a random access preamble i.e., message 1, msg1
  • the NB-IoT UE may monitor an NPDCCH search space to search for an NPDCCH for DCI scrambled with an RA-RNTI (e.g., DCI format N1).
  • the UE may receive an RAR (i.e., message 2, msg2) from the base station on an NPDSCH related to the NPDCCH.
  • the NB-IoT UE may obtain a temporary identifier (e.g., temporary C-RNTI), a timing advance (TA) command, etc. from the RAR.
  • the RAR may also provide an uplink grant for a scheduled message (i.e., message 3, msg3).
  • the NB-IoT UE may transmit the scheduled message to the base station. Then, the base station may transmit an associated contention resolution message (i.e., message 4, msg4) to the NB-IoT UE in order to inform that the random access procedure is successfully completed.
  • an associated contention resolution message i.e., message 4, msg4
  • the base station and the NB-IoT UE may complete the random access.
  • the NB-IoT UE may transition to an idle state (e.g., RRC_IDLE state) and/or an inactive state (e.g., RRC_INACTIVE state) to reduce power consumption.
  • the NB-IoT UE may be configured to operate in DRX mode.
  • the NB-IoT UE may be configured to monitor an NPDCCH related to paging only in a specific subframe (frame or slot) according to a DRX cycle determined by the base station.
  • the NPDCCH related to paging may refer to an NPDCCH scrambled with a paging access-RNTI (P-RNTI).
  • FIG. 22 illustrates an example of the DRX mode in the idle and/or inactive state.
  • FIG. 23 illustrates an example of a DRX configuration and indication procedure for the NB-IoT UE.
  • the procedure in FIG. 23 is merely exemplary, and the methods proposed in the present disclosure are not limited thereto.
  • the NB-IoT UE may receive DRX configuration information from the base station (e.g., NodeB, eNodeB, eNB, gNB, etc.) (S 2310 ).
  • the UE may receive the information from the base station through higher layer signaling (e.g., RRC signaling).
  • the DRX configuration information may include configuration information about a DRX cycle, a DRX offset, a DRX-related timer, etc.
  • the NB-IoT UE may receive a DRX command from the base station (S 2320 ).
  • the UE may receive the DRX command from the base station through higher layer signaling (e.g., MAC-CE signaling).
  • higher layer signaling e.g., MAC-CE signaling
  • the NB-IoT UE may monitor an NPDCCH in a specific time unit (e.g., subframe, slot, etc.) based on the DRX cycle (S 2330 ).
  • the NPDCCH monitoring may mean a process of decoding a specific portion of the NPDCCH based on a DCI format, which is to be received in a corresponding search space, and scrambling a corresponding CRC with a specific predefined RNTI value in order to check whether the scrambled CRC matches with (i.e. is equivalent to) a desired value.
  • the NB-IoT UE may initialize (or reconfigure) the connection (e.g., RRC connection) with the base station (for example, the UE may perform the cell search procedure of FIG. 19 ).
  • the NB-IoT UE may receive (or obtain) new system information from the base station (for example, the UE may perform the system information acquisition procedure of FIG. 19 ).
  • CRS Cell-Specific Reference Signal
  • NRS Narrowband Reference Signal
  • FIG. 24 is a diagram schematically illustrating CRS patterns applicable to the present disclosure.
  • FIG. 24 shows CRS patterns in the case of a normal CP.
  • R P denotes an RE used for transmitting an RS on antenna port p.
  • the UE may assume that CRSs are transmitted on the following resources in a cell supporting PDSCH transmission.
  • An RE used for CRS transmission on any one antenna port in a specific slot should not be used for any transmission on other antenna ports in the same slot.
  • FIG. 25 is a diagram schematically illustrating NRS patterns applicable to the present disclosure.
  • R P denotes an RE used for transmitting an RS on antenna port 2000+p.
  • the UE according to the present disclosure may assume that the NRS is transmitted as follows depending on the following conditions as follows.
  • NB-IoT and LTE cells share the same physical cell ID and have the same number of NRS ports and the same number of CRS ports). In the latter case, NB-IoT and LTE cells have different cell IDs.
  • the UE may assume that no NRS is transmitted in a subframe configured by a higher layer parameter nprsBitmap to transmit a narrowband positioning reference signal (NPRS).
  • NPRS narrowband positioning reference signal
  • the NRS may be transmitted on either or both antenna ports 2000 and 2001.
  • the UE may use the following assumptions.
  • the UE may apply the following assumptions.
  • An RE used for NRS transmission on any one antenna port in a specific slot should not be used for any transmission on other antenna ports in the same slot.
  • No NRS is transmitted in a subframe including an NPSS or NSSS
  • No NRS is transmitted in special subframes according to special subframe configurations 0 and 5 of frame structure type 2.
  • a base station may manage an anchor carrier available for NPSS/NSSS/NPBCH transmission and a non-anchor carrier, which is additionally configurable.
  • the base station may manage both the anchor and non-anchor carriers as carriers for paging.
  • a UE may monitor the anchor carrier in each DRX cycle to periodically perform radio resource management (RRM) measurement or based on relaxed RRM measurement conditions.
  • RRM radio resource management
  • the UE may perform the RRM measurement to determine whether to perform cell reselection.
  • the radio channel environment on the anchor carrier may be significantly different from that on the non-anchor carrier, and due to such a difference, there may be restrictions on paging monitoring when the UE performs paging on the non-anchor carrier.
  • anchor and non-anchor carriers may be defined as follows.
  • the corresponding configurations may be extended to all configurations interpretable in the same sense.
  • the base station may not need to transmit the NRS unless there is paging transmission.
  • the UE may not assume whether the NRS is transmitted on the non-anchor carrier until confirming the presence of an NPDCCH through blind decoding (BD).
  • BD blind decoding
  • the presence of a target RS needs to be clearly defined due to the features of the RRM measurement.
  • the RRM measurement may be unsuitable for the non-anchor carrier for paging (because whether the NRS, which is a target RS for performing the RRM measurement, is to be transmitted is unclear).
  • a wake-up signal which has been recently introduced, is to inform the UE whether a paging signal is to be transmitted before a paging occasion (PO) monitored by the UE. If it is determined based on the WUS that no paging signal is transmitted, the UE may operate/switch in/to sleep mode at a location where the paging is expected (without detecting the corresponding paging signal).
  • the UE may perform RRM measurement relaxation based on configuration information.
  • the UE may perform the RRM measurement at every N DRX cycles, instead of performing the RRM measurement at every DRX cycle.
  • the power consumption efficiency of the UE may be improved if the UE is capable of performing the WUS operation.
  • NRS transmission and reception methods on non-anchor carriers for paging
  • the NRS transmission and reception methods of the present disclosure will be described on the assumption that the NRS is transmitted in a valid subframe where the UE is always capable of expecting the NRS transmission. In other words, how the base station actually transmits the NRS to the UE will be mainly described in this document.
  • the NRS of the present disclosure may be replaced with other signals with similar purposes (e.g., WUS, additional synchronization signal, or other RSs) in some implementations.
  • the proposed methods may be implemented independently, and two or more of the proposed methods may be combined without departing from the spirit of the present disclosure.
  • the NRS transmission and reception methods proposed in the present disclosure may be combined with each or at least one of the following procedures: initial access (IA), random access (RA), and DRX of the UE.
  • IA initial access
  • RA random access
  • DRX DRX
  • the NRS transmission and reception methods proposed in the present disclosure may be performed after the IA procedure of the UE.
  • the UE may operate as follows.
  • the UE establishes a connection with the base station during the IA procedure.
  • the UE may receive parameters (or control information) predefined or preconfigured to perform the methods proposed in the present disclosure according to one of the following methods.
  • the UE may perform the methods proposed in the present disclosure (after the IA procedure) based on the parameters (or control information) received according to the above-described methods.
  • the base station may operate as follows.
  • the base station may configure for the UE the parameters (or control information) for performing the methods proposed in the present disclosure according to one of the following methods.
  • the base station may perform the methods proposed in the present disclosure (after the IA procedure) based on the corresponding parameters (or control information).
  • the NRS transmission and reception methods proposed in the present disclosure may be performed after the RA procedure of the UE.
  • the UE may operate as follows.
  • the UE establishes a connection with the base station during the RA procedure.
  • the UE may receive parameters (or control information) predefined or preconfigured to perform the methods proposed in the present disclosure according to one of the following methods.
  • the UE may perform the methods proposed in the present disclosure (after the RA procedure) based on the parameters (or control information) received according to the above-described methods.
  • the base station may operate as follows.
  • the base station may configure for the UE the parameters (or control information) for performing the methods proposed in the present disclosure according to one of the following methods.
  • the base station may perform the methods proposed in the present disclosure after the RA procedure) based on the corresponding parameters (or control information).
  • the UE may receive a NPDCCH (or MPDCCH) within the ON duration of the above-described DRX cycle and then perform NRS reception after transitioning to the RRC_CONNECTED state.
  • a NPDCCH or MPDCCH
  • the UE may operate as follows.
  • the UE may receive parameters (or control information) predefined or preconfigured to perform the methods proposed in the present disclosure according to one of the following methods.
  • the UE may perform the methods proposed in the present disclosure in the RRC_CONNECTED state based on the received parameters (or control information) after receiving a paging message in DRX mode.
  • the base station may operate as follows.
  • the base station may configure for the UE the parameters (or control information) for performing the methods proposed in the present disclosure according to one of the following methods.
  • the base station may perform the methods proposed in the present disclosure based on the received parameters (or control information) after transmitting a paging message while the UE operates in DRX mode.
  • the above-described UE and base station operations related to the IA/RA/DRX are merely examples according to the present disclosure. In some implementations, the corresponding operations may be performed in relation to all configurations proposed in the present disclosure.
  • the valid subframe in which the NRS is transmitted may mean a DL subframe where the UE may expect transmission of a DL signal for the NB-IoT.
  • the UE and base station may operate as follows regarding a DL NRS.
  • FIG. 26 is a flowchart schematically illustrating an operating method for a base station applicable to the present disclosure.
  • the base station generates an NRS sequence. Specifically, the base station generates a sequence (used) for the NRS according to Equation 2 below. In the following equations, N cell ID may be replaced with N Ncell ID .
  • Equation 2 n s denotes a slot number within a radio frame, and l denotes an OFDM symbol number within a slot.
  • N max,DL RB is a maximum DL bandwidth configuration represented by a multiple of the number of subcarriers per RB (N RB sc ).
  • a pseudo-random sequence c(i) in Equation 2 may be defined by Equation 3.
  • Such pseudo-random sequences are defined based on a length-31 Gold sequence.
  • N C is 1600.
  • a pseudo-random sequence generator may be initialized according to Equation 4 below.
  • Equation 4 c init may be initialized at the starting point of each OFDM symbol.
  • the base station maps the sequence generated by the above method to at least one RE and transmits the NRS to the UE on the RE(s).
  • the at least one RE may be a concept including at least one of a time resource, a frequency resource, or an antenna port.
  • FIG. 27 is a flowchart schematically illustrating an operating method for a UE applicable to the present disclosure.
  • the UE receives an NRS from the base station.
  • the UE may assume that the NRS is transmitted on specific RE(s).
  • the UE may receive a paging signal transmitted on a non-anchor carrier based on the received NRS. Specifically, the UE may demodulate a paging message transmitted on a PO in DRX based on the received NRS.
  • the UE may assume that the NRS is transmitted in the duration related to a paging search space, regardless of whether the paging signal is actually transmitted on the non-anchor carrier for paging.
  • the UE may assume that the NRS is transmitted in a paging search space duration regardless of whether the paging signal is actually transmitted on the non-anchor carrier where the UE expects the transmission of the paging signal.
  • the UE may assume that the NRS can be transmitted in N valid subframes after the PO.
  • the value of N may be determined by the method, which will be described in section 6.15.
  • the UE may assume that the NRS can be transmitted in N valid subframes before the PO.
  • the value of N may be determined by the method, which will be described in section 6.15.
  • the UE may assume that the NRS is transmitted in a period during which the WUS is capable of being transmitted on the non-anchor carrier for paging.
  • the UE may assume that the NRS is capable of being transmitted in the period during which the WUS is transmitted on the non-anchor carrier where the paging signal transmission is expected.
  • the base station may be configured to transmit the NRS in the period during which the WUS is transmitted on the non-anchor carrier where the paging signal transmission is expected.
  • the period during which the WUS is transmitted may be a maximum duration period allowed for WUS transmission.
  • the UE when the UE with WUS capability confirms that there is no paging signal transmission at the transmission position of the WUS, the UE may not wake up to perform measurement based on the NRS, thereby improving the power efficiency of the UE.
  • the present method may be applied only when the UE has the WUS capability.
  • the UE may (1) assume that the NRS is transmitted at an NRS transmission position, which is determined by other methods of the present disclosure, or (2) operate as in the prior art without using enhanced features related to the NRS transmission on the non-anchor carrier.
  • the UE may (1) assume that the NRS is transmitted at the NRS transmission position, which is determined by other methods of the present disclosure, or (2) operate as in the prior art without using the enhanced features related to the NRS transmission on the non-anchor carrier.
  • the UE may assume the NRS transmission position based on only the present method (NRS transmission and reception method 2). Accordingly, the base station may avoid repeating and transmitting the NRS unnecessarily.
  • the UE may assume that the NRS is capable of being transmitted in at least one subframe among N valid subframes from a starting subframe where the maximum duration of the WUS starts.
  • the UE may detect the WUS and at the same time, use the NRS.
  • the UE may assume that the NRS is capable of being transmitted in at least one subframe among N valid subframes before an ending subframe where the maximum WUS duration ends. Accordingly, it is possible to minimize the effect of the NRS on a WUS transmission period, which is for a UE capable of WUS detection within a short transmission duration, and the UE may use the NRS after detecting the WUS. Therefore, UE complexity may be reduced.
  • the value of N, the length of valid subframes in which the NRS is capable of being transmitted may be determined by the method described in section 6.15.
  • the present method may be applied only when the base station does not transmit any WUS.
  • the WUS is transmitted, if several REs of the WUS overlap with the NRS, the overlapping REs may be punctured. That is, the present method may prevent degradation in the performance of WUS detection.
  • the UE may perform measurement or tacking on the assumption that either the WUS or NRS is transmitted.
  • the base station may provide the UE with information about the transmit power of the WUS and/or quasi-colocation (QCL) information.
  • QCL quasi-colocation
  • the WUS puncturing by the NRS may be applied when the base station or UE does not transmit a specific signal at a specific resource position or does not receive the specific signal. For example, if there is an overlap between specific signals (or specific RE(s)), the base station or UE may puncture a part of the overlapping signal(s) at the location where the overlap occurs.
  • the UE may assume that the NRS is capable of being transmitted in N valid subframes adjacent to a period capable of WUS transmission on the non-anchor carrier for paging.
  • the UE may assume that the NRS is transmitted in at least one subframes among valid subframes adjacent to a period during which the WUS is transmitted on the non-anchor carrier where the paging signal transmission is expected.
  • the base station may transmit the NRS after the period during which the WUS is transmitted on the non-anchor carrier where the paging signal transmission is expected.
  • the period during which the WUS is transmitted may be a maximum duration period allowed for WUS transmission.
  • the present method may have the same advantages as NRS transmission and reception method 2. In addition to that, the present method may solve both WUS puncturing issues caused by the NRS transmission and UE complexity problems.
  • WUS capability related operations may be the same as the operations described above in NRS transmission and reception method 2.
  • the UE may assume that the NRS is capable of being transmitted in at least one subframe among N valid subframes before a starting subframe where the maximum WUS duration starts. Accordingly, before detecting the WUS, the UE may determine whether to perform cell reselection by performing RRM measurement on the corresponding carrier (i.e., non-anchor carrier) or be provided with a warm-up time for channel estimation.
  • the corresponding carrier i.e., non-anchor carrier
  • the UE may assume that the NRS is capable of being transmitted in at least one subframe among N valid subframes after an ending subframe where the maximum WUS duration ends.
  • the UE may perform NRS monitoring by operating a main receiver only when the WUS is present, and this operation may be particularly suitable for a low-complexity UE.
  • a prescribed (time) gap may be present or configured between the WUS transmission period and the period during which the NRS transmission is assumed.
  • the UE may be provided with a time for processing the NRS and WUS and a preparation time therefor.
  • the value of N, the length of valid subframes in which the NRS is capable of being transmitted may be determined by the method described in section 6.15.
  • the base station When the base station (or network) supports the WUS, the base station may periodically configure a WUS without DTX for the UE.
  • WUS without DTX may mean that the WUS is always transmitted.
  • the present method proposes that when the UE supports the WUS, the base station periodically configures a ‘WUS without DTX’ period for the UE.
  • the WUS without DTX may be interpreted to mean that the WUS is always transmitted regardless of whether a following related paging signal is transmitted or not.
  • an operation in which the WUS is transmitted if there is transmission of a following related paging signal and otherwise, the WUS is not transmitted as in the WUS defined in Rel-15 NB-IoT may be referred to “‘WUS with DTX”.
  • the base station may achieve the same purpose as that of the NRS by using an RS such as the WUS, instead of additionally transmitting the NRS on the non-anchor carrier.
  • the WUS without DTX and WUS with DTX may share a transmission position.
  • the base station may transmit the WUS without DTX at the position of the WUS with DTX defined in Rel-15 NB-IoT.
  • the transmission period of the WUS without DTX may be L times greater than that of the WUS with DTX.
  • the value of L may be determined according to one of the following options.
  • the value of L may be explicitly configured by higher layer signaling such as an SIB or RRC signaling.
  • the base station may achieve flexible resource management.
  • the value of L may be determined by the level of RRM measurement relaxation. According to Option 2, when the RRM measurement relaxation is configured for the UE supporting the WUS and when the WUS without DTX is used for RRM measurement, it is possible to prevent unnecessary WUS transmission.
  • the configuration/application of the WUS without DTX may be determined for each carrier. That is, individual carriers may have different radio channel environments and different traffic, and thus whether the present method is enabled or disabled for a specific carrier may be determined based thereon.
  • the WUS without DTX may be configured/applied for/to only the non-anchor carrier. Since synchronization signals such as NPSS/NSSS are transmitted on the anchor carrier and the assumption that the NRS is always transmitted in the valid subframe is made for the anchor carrier, the WUS without DTX may be configured/applied for/to only the non-anchor carrier to avoid an unnecessary increase in signaling overhead.
  • the WUS without DTX may include a WUS that can be identified by only UEs capable of recognizing the WUS without DTX.
  • a legacy WUS e.g., WUS that can be recognized by even UEs without capability for the WUS without DTX
  • an additional WUS e.g., WUS that can be recognized by only UEs with capability for the WUS without DTX
  • the additional and legacy WUSs may be identified by at least one of sequences and resources distinguished in the time and/or frequency domain.
  • the UE may recognize that there is no following related paging signal after detecting the additional WUS. That is, the UE may perform go-to-sleep operation where paging monitoring is not performed. Further, according to the present method, the base station may provide an RS for the UE and at the same time, avoid unnecessary operations for paging.
  • the WUS without DTX may be configured to be transmitted in at least N min valid subframes. Accordingly, the base station may provide a minimum transmission length for measurement and tracking to the UE.
  • the value of N min may be determined by any combination of one or more of the following options.
  • N min may be determined based on a function having as an input R max , where R max denotes a maximum number of times that an NPDCCH can be repeated and transmitted in a paging search space.
  • R max may be determined by maximum coverage supported by the base station.
  • N min may be determined by a function having as an input the size of the maximum WUS duration.
  • N min may be determined by the actual transmission duration of the WUS (e.g., 2 N unit).
  • N min (Opt.4) If the value of N min calculated according to specific standards is greater than the maximum WUS duration, the value of N min may be determined to be equal to the maximum WUS duration.
  • a common NRS transmission duration may be configured for a plurality of UEs irrespective of UE_IDs.
  • the UE may assume the duration of valid subframes where periodic NRS transmission is guaranteed UE-commonly on the non-anchor carrier (where the paging signal transmission is expected) for each cell (or each carrier).
  • the base station may minimize the number of valid subframes required for the NRS transmission, thereby reducing signaling overhead.
  • the determination of the NRS transmission period (i.e., valid subframes in which the NRS is transmitted) described in the present method may be applied to transmit any signal that can be used for similar purposes (e.g., a signal with the similar purpose and structure to the resynchronization signal (RSS) introduced in Rel-15 MTC).
  • RSS resynchronization signal
  • the base station may configure the location and generation period of a reference subframe, where the NRS transmission starts, for the UE through higher layer signaling such as an SIB or RRC signaling.
  • the location of the reference subframe may be the first valid subframe on frame numbers, which are expressed by the system frame number (SFN) or hyper frame number (HFN) (or hyper SFN).
  • the value of N, the number (or length) of valid subframes in which the NRS is capable of being transmitted may be determined by the method described in section 6.15.
  • the UE may determine/assume the duration of valid subframes in which the NRS is always transmitted based on the level of the RRM measurement relaxation.
  • the methods proposed in the present disclosure may be applied as follows.
  • the period of a PO capable of assuming the valid subframe where the NRS transmission is always guaranteed described in NRS transmission and reception method 1; the location and generation period of a WUS capable of assuming the valid subframe where the NRS transmission is always guaranteed described in NRS transmission and reception methods 2 and 3; the generation period of a WUS without DTX described in NRS transmission and reception method 4; and the generation period of an NRS burst described in NRS transmission and reception method 5 may be determined according to the present method.
  • the NRS of the present method may be extended to a WUS and burst NRS (or RS).
  • the present method may be applied only when the UE has WUS capability.
  • the reason for this is that the RRM measurement relaxation may be configured for only the UE with the WUS capability.
  • a period capable of assuming the NRS valid subframe may be configured to be equivalent to the level of the RRM measurement relaxation.
  • the UE may assume the valid subframe in which the NRS is always transmitted is equally configured for the X DRX cycles.
  • each UE may determine as the reference point the first PO in a paging transmission window (PTW) after an eDRX cycle.
  • PGW paging transmission window
  • the UE may determine the valid subframe capable of assuming the NRS transmission in a different way depending on whether the UE operates in eDRX mode.
  • the present method proposes that the UE configures the valid subframe capable of assuming the NRS transmission differently depending on whether the UE operates in the eDRX mode.
  • the assumption about the NRS transmission valid subframe proposed in the present method may be applied to only a UE that does not use the eDRX mode. This is because a UE operating in the eDRX mode needs to perform NPSS/NSSS/NPBCH monitoring to acquire time/frequency synchronization and check/obtain system information. That is, in this case, the UE needs to monitor the anchor carrier and thus does not require the NRS assumption for the non-anchor carrier.
  • the assumption about the NRS transmission valid subframe may be applied to only a UE operating in the eDRX mode.
  • NRS transmission and reception method 7 may be performed together with NRS transmission and reception methods 2 to 4.
  • NRS transmission and reception method 7 when NRS transmission and reception method 7 is used, if the NRS (or WUS without DTX) transmission and reception method based on the transmission position of the WUS, which is described above in NRS transmission and reception methods 2 to 4, is combined therewith, the UE may be configured to assume the NRS transmission valid subframe only at the location of a specific size of gap. In other words, the UE may assume the valid subframe capable of assuming the NRS transmission only for the specific size of gap.
  • the base station may manage gap 1 and gap 2 (where gap 1>gap 2) to support all UEs.
  • gap 1>gap 2 the location of a gap used by the UE as the NRS transmission position to assume the NRS transmission may be fixed either gap 1 or gap 2.
  • the UE may assume that the NRS may be transmitted at a WUS transmission position determined with respect to the location of another gap.
  • the UE may be configured to assume that the NRS is transmitted only at the location of a gap related to its gap capability. In this case, the UE may be configured not to expect the NRS at locations of other gaps.
  • the UE may assume the valid subframe in which the NRS is transmitted (including the methods proposed in the present disclosure) (i) based on the duration of DRX (or eDRX) configured in a cell, (ii) regardless of whether the paging signal is transmitted on the non-anchor carrier for paging.
  • the UE may implicitly recognize the assumption about the valid subframe where the NRS transmission is always expected on non-anchor carrier for paging (i) without any extra configurations (ii) based on the duration of DRX (or eDRX).
  • the UE may be configured to assume the valid subframe where the NRS transmission is always expected (including the methods proposed in the present disclosure) only when the duration of DRX (or eDRX) is less than a predetermined value.
  • the UE may need to check synchronization signals and system information on the anchor carrier before performing NRS-based operations.
  • the UE may assume the valid subframe in which the NRS is transmitted (including the methods proposed in the present disclosure) (i) based on the mode of the non-anchor carrier for paging (ii) regardless of whether the paging signal is transmitted.
  • the UE may implicitly recognize the assumption about the valid subframe where the NRS transmission is always expected based on the mode of the non-anchor carrier for paging.
  • the UE may apply the assumption about the NRS transmission on the non-anchor carrier for paging only when the mode of the non-anchor carrier is a specific operation mode. For example, when the non-anchor carrier is present in an in-band, the UE may be configured not to use the assumption about the NRS transmission to guarantee signal overhead for the legacy LTE system. However, since there are no restrictions on non-anchor carriers configured for the guard-band or standalone system, the UE may be configured to apply the assumption about the NRS transmission.
  • the UE may receive the configuration of the NRS on the non-anchor carrier per operation mode of the non-anchor carrier from the base station.
  • the base station may transmit/indicate to the UE configuration information on the valid subframe where the UE is capable of expecting the NRS transmission at all times per operation mode, in which a carrier managed by the base station is present, through higher layer signaling such as an SIB or RRC signaling.
  • the operation mode of the non-anchor carrier is in-band same PCI mode
  • the UE may assume that common reference signals or cell-specific reference signals (CRSs) are transmitted in specific subframes.
  • CRSs cell-specific reference signals
  • the locations of the specific subframes for CRS transmission may be determined in the same way when the NRS transmission on the non-anchor carrier for paging is assumed in other operation modes.
  • the UE may be configured not to assume the NRS transmission on a part of the corresponding carrier where the CRS transmission is assumed. According to the present method, since the NRS transmission may not be performed if there is no paging signal transmission, the effects on signal transmission for other LTE services may be minimized.
  • the UE may assume that CRSs are transmitted in specific subframes.
  • additional information is required for the UE to detect a CRS transmitted on a specific time/frequency resource.
  • the additional information may include information about a CRS-to-NRS power offset and information about the location of the corresponding frequency resource in the LTE system bandwidth.
  • the base station may provide the additional information to the UE.
  • the UE may expect that an additional NRS is transmitted in a paging-related subframe (as in the guard-band and standalone system) if the number of CRS antenna ports is 4.
  • the present method may be applied to only UEs that do not know whether an NPDCCH or NPDSCH is transmitted in a specific period. In other words, if the UE knows or is capable of knowing whether the NPDCCH or NPDSCH is transmitted, the UE may assume that the NRS is always transmitted in the entirety (or a part) of a period where the CRS transmission is assumed because both the NRS and CRS are transmitted.
  • FIG. 28 is a diagram schematically illustrating an NRS transmission and reception method according to an implementation of the present disclosure.
  • FIG. 28 ( a ) shows a case in which both the NRS and CRS are assumed to be transmitted at the same time
  • FIG. 28 ( b ) shows a case in which only the CRS is assumed to be transmitted.
  • the location of the valid subframe in which the NRS is transmitted may be configured based on a relative gap from a PO.
  • the UE may determine the location of the valid subframe where the NRS transmission is always expected based on the relative gap from the PO. According to the present method, the UE may measure the NRS before monitoring the paging signal and obtain a warm-up time for preparing a follow-up operation.
  • the gap may be defined as an interval between the starting subframe (or ending subframe) of the valid subframe in which the NRS is transmitted and the PO.
  • the size of the gap may be (1) predefined by standards or (2) indicated by higher layer signaling such as an SIB or RRC signaling.
  • the present method may be applied only when there is no WUS configuration for the base station or UE.
  • the UE may assume NRS-related operations by maintaining a structure similar thereto, thereby simplifying the operation of the UE.
  • the present method may be applied when there is a WUS configuration for the base station or UE but the UE has no WUS capability.
  • the base station may transmit the NRS at the same NRS transmission position as that of a WUS-capable UE.
  • the definition of the PO may be extended to the starting subframe of the maximum WUS duration or the ending subframe of the maximum WUS duration.
  • a period in which the NRS (or WUS without DTX) is transmitted may be determined based on the transmission position of the WUS.
  • the UE may assume that the NRS is transmitted in at least one subframe among N valid subframes adjacent to a period in which a WUS for a specific UE sub-group is transmitted on the non-anchor carrier for paging.
  • the UE may assume that the NRS is transmitted in the period in which the WUS for the specific UE sub-group or in the valid subframes adjacent thereto on the non-anchor carrier (where the paging signal is expected). That is, the base station may be configured to transmit the NRS in the period in which the WUS for the specific UE sub-group is transmitted or in the valid subframes adjacent thereto on the non-anchor carrier.
  • the UE sub-grouping may refer to dividing UEs that expect reception of a paging NPDCCH on the same PO into a plurality of groups.
  • a sub-group WUS may refer to a WUS allocated to each UE sub-group on resources distinguished in the time, frequency, and/or code domain.
  • the present method is described in terms of NRS transmission and reception.
  • the features of the NRS may be similarly applied to other signals such as an RS, a WUS without DTX, etc.
  • a time-domain resource may be configured for each sub-group WUS.
  • the UE may be configured to assume the (valid) subframe in which the NRS is transmitted for only a WUS using a specific time-domain resource (alternatively, the UE may be configured to assume that the NRS is transmitted at position related to one or multiple time-domain WUS resources).
  • the specific time-domain resource may be a time-domain resource with the earliest starting position among starting subframes of individual sub-group WUSs.
  • the UE may perform NRS-based measurement before transmitting its WUS, regardless of which UE sub-group the UE belongs to.
  • the specific time-domain resource may be a time-domain resource of a WUS that can be used by a UE with no UE sub-group capability.
  • the UE may perform the NRS-based measurement even though the UE has no UE sub-group capability.
  • the specific time-domain resource may be a time-domain resource that is the most monitored by UEs among multiple UE sub-group WUSs (preferably, a sub-group WUS that should be monitored by all UEs). If UEs do not accurately know the corresponding time-domain resource, the base station may provide additional information to the UEs to allocate the corresponding resource to the UEs.
  • the UE may know and use the WUS transmission position of a UE sub-group that is the reference of the NRS transmission regardless of the UE sub-group (to which the UE belongs).
  • the present method may prevent an increase in NRS overhead, which may increase independently of whether the WUS is transmitted, when WUS overhead increases due to use of the UE sub-grouping.
  • the UE is capable of assuming the NRS transmission in the duration of a paging search space, regardless of whether the paging signal is transmitted on the non-anchor carrier for paging.
  • the operation mode of the corresponding non-anchor carrier is the in-band same PCI mode. Based on the above assumption, it is proposed that the UE does not assume (or expect) that the CRS is transmitted in the entirety (or a part) of a period in which the NRS transmission is assumed.
  • the UE may be configured to not assume the CRS transmission in the valid subframe in which the NRS transmission is always expected.
  • the present method may be suitable for when the base station supporting legacy LTE supports CRS muting in a duration of several subframes.
  • the base station may be configured to transmit no CRS in specific subframe(s) to control interference to neighboring base stations.
  • a UE operating according to Rel-15 standards i.e., NB-IoT UE
  • the UE may not apply the assumption about the CRS muting subframe.
  • the corresponding UE may expect that the CRS is always transmitted in the subframe in which the NRS is transmitted.
  • the UE operating according to the recent standards may expect both the NRS transmission and CRS transmission.
  • the base station may be forced to transmit the CRS in the subframe to which the CRS muting is applied. If a specific UE becomes capable of assuming the NRS transmission at many positions, the effects expected from the application of the CRS muting by the base station or other UEs may decrease.
  • the UE may be restricted not to assume the CRS transmission in the subframe in which the NRS transmission is assumed. Accordingly, the base station connected with the UE may avoid the unnecessary and forced CRS transmission.
  • the base station may configure a subframe duration in which the NRS is always transmitted regardless of whether the paging signal is transmitted on the non-anchor carrier.
  • the base station may determine whether to transmit the CRS in the entirety (or a part) of the subframe duration (in which the NRS is transmitted) depending on situations, for example, a CRS muting configuration and so on.
  • the UE may receive information about the subframe duration in which the UE is capable of assuming the NRS and then assume that the NRS is transmitted in the corresponding subframe duration based on the information. However, the UE may not assume the CRS transmission based on only the configuration information about the subframe duration in which the NRS transmission is assumed.
  • the base station may transmit the CRS in some or all of the NRS transmission positions. For example, the base station may transmit the CRS in only (i) a subframe where the CRS muting is not applied or (ii) a subframe where an NPDCCH or NPDSCH is actually transmitted among resources for the NRS transmission.
  • the present method may be applied to only UEs that do not know whether the NPDCCH or NPDSCH is actually transmitted in a specific period.
  • the UE may assume that the CRS is always transmitted in the entirety (or a part) of a period where the NRS transmission is assumed because both the NRS and CRS are transmitted.
  • the UE or base station may use only several POs among all POs as a reference value (or input value) for determining the locations of subframes in which the NRS is transmitted.
  • a reference value or input value
  • the UE or base station may use the subframe number of a PO and/or the SFN of a PF as the reference value for selecting the several POs.
  • the present method proposes that when a subframe in which the NRS is transmitted is determined based on a PO, the UE or base station selects POs including subframes in which the NRS is transmitted.
  • the locations of subframes in which the UE is capable of assuming the NRS transmission regardless of the paging signal transmission may be determined as relative locations with respect to POs.
  • the POs may be all or several POs managed by the base station.
  • the UE may use POs that satisfy Equation 5 below when determining the locations of subframe(s) in which the NRS transmission is assumed.
  • S mod R ( Q +1)mod 2 [Equation 5]
  • Equation 5 S denotes the SFN of a PF in which a PO is located, and Q denotes a subframe number (i.e., the index of a subframe in one frame where the PO is located).
  • the base station may transmit the NRS in a subframe corresponding to the PO according to predetermined rules even though no paging signal is transmitted on the corresponding PO.
  • the UE may assume that the NRS is transmitted in the subframe corresponding to the PO.
  • the base station may not transmit the NRS if the base station transmits no paging signal on the corresponding PO.
  • the UE may be configured not to assume the NRS transmission based on the PO, which does not satisfies Equation 5 and has no paging signal transmission.
  • R is a value for determining the generation period of a subframe including the NRS.
  • the value of R may be predefined by standards.
  • the value of R may be fixed to 2.
  • T refers to a DRS cycle of the UE
  • nB is a parameter used for calculating an NB-IoT paging carrier and may have one of the following values: 4T, 2T, T, T/2, T/4, T/8, T/16, T/32, T/64, T/128, T/256, T/512, and T/1024.
  • the value of nB may be configured by PCCH-Config-NB-r13 in a higher layer parameter RadioResourceConfigCommonSIB-NB. When nB>T/2, the number of subframes in which the NRS is transmitted may not be set to a large value because the PO is present every three frames.
  • the value R may be fixed to 1.
  • the number of subframes in which the NRS is transmitted may be constant for each PO.
  • the base station may not transmit any signaling for determining an NRS transmission pattern to the UE.
  • R of Equation 5 may be semi-statically configured by the base station through higher layer signaling such an SIB or RRC signaling.
  • the value of R may determine the generation period of the NRS transmission pattern.
  • the value of R may determine the density of subframes in which the base station needs to transmit the NRS at all times, regardless of whether the paging signal is transmitted.
  • the base station may increase the NRS density by decreasing the value of R.
  • the value of R may be determined by the paging parameter nB used to determine the PO.
  • the paging parameter nB denotes the number of POs existing within one paging cycle for all UEs in a cell. Thus, the paging parameter nB may be used to determine a spacing between different POs.
  • frames on all SFNs may include two or more PO. Based on that, R may be set to 2 in the case of nB ⁇ 2T, and R may be set to 1 in the case of nB ⁇ 2T.
  • the base station may adjust the number of NRS transmission subframes based on the value of R by reducing the occurrence frequency of POs in which the NRS is transmitted.
  • the base station may configure the NRS subframe over all POs based on the value of R such that UEs monitoring each PO may equally use the NRS.
  • POs monitored by UEs with certain UE_IDs may include no NRS subframes (directly) related thereto.
  • the UE may use the locations of subframes related to neighboring POs (rather than the POs that the UEs should monitor). According to this configuration, there may be a difference between gains obtained by the UEs due to a time difference between the NRS subframe and actual PO.
  • Equation 5 may be modified into Equation 6.
  • Equation 6 the method of determining the location of a NRS transmission subframe may be periodically changed.
  • S mod R ( Q + ⁇ )mod 2 [Equation 6]
  • the value of ⁇ may be determined by the SFN.
  • the value of ⁇ may be determined as either 0 or 1 at a period of T frames.
  • Equation 5 Since the above-described issues of Equation 5 occurs only when nB is greater than or equal to T, the value of ⁇ may be determined according to Equation 7 depending on the value of nB.
  • the UE may determine the location of a subframe in which the NRS transmission is assumed as follows.
  • the UE may assume that the NRS is transmitted in first N1 subframes among 10 valid subframes (or NB-IoT DL subframes) prior to the PO (such a frame is referred to as a first frame) and N2 consecutive valid subframes (or NB-IoT DL subframes) after the PO (such a frame is referred to as a second frame).
  • the base station may be configured to transmit the NRS in the first N1 subframes among the 10 valid subframes (or NB-IoT DL subframes) prior to the PO (i.e., N1 first subframes) and the N2 consecutive valid subframes (or NB-IoT DL subframes) after the PO (i.e., N2 second subframes).
  • the values of N1 and N2 may be determined based on the value of nB and/or the number of valid subframes (i.e., NB-IoT DL subframes) in one frame.
  • horizontal hatching or hatching in the middle row for each nB value
  • inclined hatching or hatching in the bottom row for each nB value
  • the location and duration of the subframe in which the NRS is transmitted may be determined by the value of nB.
  • a PO including the subframes in which the NRS is transmitted may be used as a reference value for determining the subframes in which the NRS is transmitted.
  • the locations of the subframes in which the NRS transmission is assumed may be determined as relative locations with respect to POs.
  • the POs may be some or all POs managed by the base station.
  • the UE may use all POs located at subframe #9 to determine the locations of the subframes in which the NRS transmission is assumed.
  • the locations of the subframes in which the NRS is transmitted may be determined based on subframe #9 of the frame including the PO.
  • the PO may be included in every frame from the perspective of the base station.
  • the PO may be located at subframe #9 in every frame, and the locations of the subframes in which the NRS is transmitted (or the NRS transmission is assumed) may be determined based on every PO.
  • every frame may include one or more POs from the perspective of the base station.
  • the locations of the subframes in which the NRS is transmitted may be determined based on a PO corresponding to subframe #9 among one or more POs included in a frame.
  • the length of one NRS subframe corresponding to each PO may be determined by the value of nB.
  • the NRS may be transmitted in first N1 subframes among 10 valid subframes (or NB-IoT DL subframes) prior to the PO (such a frame is referred to as a first frame) and N2 consecutive valid subframes (or NB-IoT DL subframes) after the PO (such a frame is referred to as a second frame).
  • the UE may assume that the NRS is transmitted in the first and second subframes.
  • the values of N1 and N2 may be determined based on the value of nB and/or the number of valid subframes (i.e., NB-IoT DL subframes) in one frame.
  • the UE may always expect the NRS transmission at fixed location(s) without solving a complicated formula and judging a condition.
  • the base station may adjust the number of subframes required for the NRS transmission to be suitable for the density of POs.
  • the number of valid subframes in which the NRS is transmitted (or the NRS transmission is assumed) N may be determined by one of the following methods: first to eighth methods for determining the number of valid subframe or any combination of two or more of the methods.
  • the minimum duration of the valid subframe in which the UE is capable of expecting the NRS transmission may be provided.
  • the UE may assume that at least N valid subframes are always available for the NRS transmission regardless of whether the paging signal or WUS is transmitted. Accordingly, the base station may guarantee that the UE performs measurement or tracking based on the NRS.
  • the number of valid subframes in which the NRS is transmitted (or the NRS transmission is assumed) N may be predetermined by specifications.
  • the UE may determine the value of N according to the first method for determining the number of valid subframe.
  • the number of valid subframes in which the NRS is transmitted (or the NRS transmission is assumed) N may be determined by a function having as an input R max , which is configured for a search space for paging.
  • the base station may adjust the number of valid subframes in which the NRS is transmitted (or the NRS transmission is assumed), thereby controlling/reducing signaling overhead.
  • the UE and base station may determine the number of NRS-related valid subframes with no additional signaling.
  • the number of valid subframes included in the NRS transmission N may be configured to satisfy Equation 8 below.
  • N R max* ⁇ [Equation 8]
  • N may be configured to satisfy the following condition at all times: N is more than or equal to a minimum size N S and/or less than or equal to a maximum size N L .
  • ⁇ is a scaling factor, where a may (1) have a fixed value determined by specifications or (2) be indicated by higher layer signaling such as an SIB or RRC signaling.
  • a relationship between the number of valid subframes included in the NRS transmission N and R max may be specified in a specific table.
  • the UE and base station may select the value of N with respect to the value of R max based on the specific table.
  • the number of valid subframes in which the NRS is transmitted (or the NRS transmission is assumed) N may be indicated by higher layer signaling (e.g., SIB or RRC signaling) received from the base station.
  • higher layer signaling e.g., SIB or RRC signaling
  • the base station may manage the number of valid subframes used for the NRS transmission flexibly depending on network situations.
  • the number of valid subframes N may be configured (independently) for each cell, thereby reducing base station signaling overhead related to the number of valid subframes.
  • the number of valid subframes N may be configured for each carrier. Accordingly, the base station may configure the number of valid subframes for the NRS in consideration of a difference in radio channel environments such as applicability of power boosting for each carrier.
  • the number of valid subframes in which the NRS is transmitted (or the NRS transmission is assumed) N may be determined by a function having as an input the size of the maximum WUS duration.
  • the base station may adjust (for example, reduce) the number of valid subframes used for the NRS transmission, thereby reducing signaling overhead.
  • the UE and base station may (implicitly) determine the number of valid subframes for the NRS based on the value of R max differently configured for each carrier, whereby no additional signaling is required.
  • the number of valid subframes included in the NRS transmission N may be configured to satisfy Equation 9 below.
  • N R WUS_max * ⁇ [Equation 9]
  • R WUS_max denotes the maximum duration of the WUS.
  • N When the number of NRS-related valid subframes N is determined by Equation 9, the value of N may be configured to satisfy the following condition at all times: N is more than or equal to a minimum size N S and/or less than or equal to a maximum size N L .
  • ⁇ is a scaling factor, where ⁇ may (1) have a fixed value determined by specifications or (2) be indicated by higher layer signaling such as an SIB or RRC signaling.
  • a relationship between the number of valid subframes included in the NRS transmission N and R WUS_max may be specified in a specific table.
  • the UE and base station may select the value of N with respect to the value of R WUS_max based on the specific table.
  • the number of valid subframes in which the NRS is transmitted (or the NRS transmission is assumed) N may be determined for each paging search space candidate.
  • the value of N and the duration of a valid subframe may be determined by the same rules as those for configuring a paging search space candidate.
  • the UE may be configured to use the NRS based on candidate values of N.
  • minimum standards for the UE to use the NRS may be provided, thereby reducing UE complexity.
  • the base station may flexibly adjust the number of valid subframes used for the NRS transmission depending on network situations.
  • the number of valid subframes in which the NRS is transmitted (or the NRS transmission is assumed) N may be determined by the actual transmission duration of the WUS.
  • the value of N and the duration of a valid subframe may be determined by the same rules as those for the actual transmission duration.
  • the UE may be configured to use the NRS based on candidate values of N.
  • minimum standards for the UE to use the NRS may be provided, thereby reducing UE complexity.
  • the base station may flexibly adjust the number of valid subframes used for the NRS transmission depending on network situations.
  • the number of valid subframes in which the NRS is transmitted (or the NRS transmission is assumed) N may be restricted to be more than or equal to (or less than or equal to) a specific value.
  • the base station may prevent an increase in overhead caused by unnecessary NRS transmission.
  • the upper limit of N is N max and the value of N calculated/configured by a specific method is N′
  • both the upper limit (N max ) and lower limit (N min ) may be set for N.
  • the number of valid subframes in which the NRS is transmitted (or the NRS transmission is assumed) N may be determined by operation modes.
  • the base station and UE may configure/assume a relatively short NRS transmission duration in consideration of the additional available information.
  • the base station and UE may configure/assume the number of valid subframes for the NRS transmission in consideration of subframes used for other signal transmission except NB-IoT transmission in several operation modes.
  • N1 and N2 may be configured to satisfy the following condition: N1 ⁇ N2.
  • the UE may obtain additional information based on CRS assumption(s) provided in the in-band same PCI mode, and in this case, the NRS transmission duration may be set to be relatively short compared to other operation modes.
  • the number of valid subframes where the NRS transmission is assumed N may be fixed to specific values depending on operation modes by standards.
  • the UE and base station may obtain related information without extra signaling overhead.
  • the number of valid subframes where the NRS transmission is assumed N may be configured to have a prescribed ratio or offset for each operation mode.
  • the prescribed ratios or offsets may be fixed by standards.
  • the UE and base station may obtain related information without additional signaling about the number of valid subframes for each operation mode.
  • FIG. 30 is a flowchart schematically illustrating a method for a UE to receive an NRS according to an implementation of the present disclosure.
  • the UE checks whether there is a specific PO satisfying specific condition(s) among a plurality of POs related to the UE (S 3001 ).
  • NRS transmission and reception method 13 or 14 described above may be used.
  • S mod R (Q+1)mod 2. This may be interpreted to mean that the remainder of dividing the SFN of a PF in which a PO is located by R is equal to the remainder of dividing a value obtained by adding 1 to the number of a subframe including the PO by 2.
  • the PO that satisfies the above condition may be regarded as the specific PO.
  • Q+1 since the SFN has a value of 0 to 9, Q+1 may have a value of 1 to 10.
  • the value of Q may be an even number such as 0, 2, 4, 6, or 8 because the remainder of dividing (Q+1) by 2 should be 1.
  • the value of Q may be an odd number such as 1, 3, 5, 7, or 9 because the remainder of dividing (Q+1) by 2 should be 0.
  • the specific PO is determined depending on whether the subframe number in which the PO is located is even or odd.
  • S mod R (Q+a)mod 2. This may be interpreted to mean that the remainder of dividing the SFN of a PF in which a PO is located by R is equal to the remainder of dividing a value obtained by adding a to the number of a subframe including the PO by 2.
  • the PO that satisfies the above condition may be regarded as the specific PO.
  • a PO may be the specific PO when the number of a subframe in which the PO is located is a specific number.
  • the PO may be the specific PO only when the subframe number in which the PO is located is 9.
  • the UE determines a time period for receiving the NRS based on the specific PO (S 3002 ).
  • the UE receives the NRS in the determined time period (S 3003 ).
  • the NRS is taken as an example, the UE may receive a CRS together with the NRS or receive only the CRS without the NRS.
  • FIG. 31 is a flowchart schematically illustrating an NRS transmission and reception method between a UE and base station according to an implementation of the present disclosure.
  • the UE determines a specific PO from among a plurality of POs according to predetermined rules (S 3102 ).
  • the base station generates an NRS (S 3101 ) and then transmits the NRS to the UE in a time period determined based on the specific PO according to the predetermined rules (S 3103 ).
  • the UE receives the NRS from the base station in the time period determined based on the specific PO (S 3104 ).
  • the UE may receive a CRS together with the NRS or receive only the CRS without the NRS.
  • each of the examples of the proposed methods may be included as one method for implementing the present disclosure, it is apparent that each example may be regarded as a proposed method.
  • the proposed methods may be implemented independently, some of the proposed methods may be combined (or merged) for implementation.
  • it may be regulated that information on whether the proposed methods are applied (or information on rules related to the proposed methods) should be transmitted from a base station to a UE through a predefined signal (e.g., a physical layer signal, a higher layer signal, etc.).
  • FIG. 32 illustrates a communication system 1 applicable to the present disclosure.
  • the communication system 1 applicable to the present disclosure includes wireless devices, base stations, and a network.
  • the wireless device represents a device performing communication based on a radio access technology (e.g., 5G NR, LTE, etc.) and may be referred to as a communication/radio/5G device.
  • the wireless devices may include, but not limited to, a robot 100 a , vehicles 100 b - 1 and 100 b - 2 , an extended reality (XR) device 100 c , a hand-held device 100 d , a home appliance 100 e , an Internet of things (IoT) device 100 f , and an artificial intelligence (AI) device/server 400 .
  • XR extended reality
  • IoT Internet of things
  • AI artificial intelligence
  • the vehicles may include a vehicle having a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing communication between vehicles.
  • the vehicles may include an unmanned aerial vehicle (UAV) (e.g., a drone).
  • UAV unmanned aerial vehicle
  • the XR device may include an augmented reality/virtual reality/mixed reality (AR/VR/MR) device and be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) mounted in vehicles, a television (TV), a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc.
  • the hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), and a computer (e.g., a notebook).
  • the home appliance may include a TV, a refrigerator, and a washing machine.
  • the IoT device may include a sensor and a smart meter.
  • the network and base stations may be implemented as wireless devices, and a specific wireless device 200 a may operate as a base station/network node for other wireless devices.
  • the wireless devices 100 a to 100 f may be connected to the network 300 via the base stations 200 .
  • An AI technology may be applied to the wireless devices 100 a to 100 f , and the wireless devices 100 a to 100 f may be connected to the AI server 400 via the network 300 .
  • the network 300 may include a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network.
  • the wireless devices 100 a to 100 f may communicate with each other through the base stations/network 200 / 300
  • the wireless devices 100 a to 100 f may perform direct communication (e.g., sidelink communication) with each other without assistance from the base stations/network 200 / 300 .
  • the vehicles 100 b - 1 and 100 b - 2 may perform direct communication (e.g. V2V/V2X communication).
  • the IoT device e.g., a sensor
  • the IoT device may perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100 a to 100 f.
  • Wireless communication/connections 150 a , 150 b , or 150 c may be established between the wireless devices 100 a to 100 f and base stations 200 or between one base station 200 and another base station 200 .
  • the wireless communication/connections may be established through various RATs (e.g., 5G NR) such as UL/DL communication 150 a , sidelink communication 150 b (or D2D communication), or inter-base station communication (e.g. relay, integrated access backhaul (IAB), etc.).
  • the wireless devices and base stations may transmit/receive radio signals to/from each other through the wireless communication/connections 150 a to 150 c .
  • signals may be transmitted/received over various physical channels for the wireless communication/connections 150 a to 150 c .
  • various configuration information configuring processes e.g., channel encoding/decoding, modulation/demodulation, resource mapping/demapping, etc.
  • resource allocating processes for radio signal transmission/reception may be performed based on the various proposals of the present disclosure.
  • FIG. 33 illustrates a wireless device applicable to the present disclosure.
  • a first wireless device 100 and a second wireless device 200 may transmit radio signals through a variety of RATs (e.g., LTE and NR).
  • ⁇ the first wireless device 100 and the second wireless device 200 ⁇ may correspond to ⁇ the wireless device 100 x and the base station 200 ⁇ and/or ⁇ the wireless device 100 x and the wireless device 100 x ⁇ of FIG. 33 .
  • the first wireless device 100 may include one or more processors 102 and one or more memories 104 and additionally further include one or more transceivers 106 and/or one or more antennas 108 .
  • the processor(s) 102 may control the memory(s) 104 and/or the transceiver(s) 106 and may be configured to implement the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document.
  • the processor(s) 102 may process information within the memory(s) 104 to generate first information/signals and then transmit radio signals including the first information/signals through the transceiver(s) 106 .
  • the processor(s) 102 may receive radio signals including second information/signals through the transceiver 106 and then store information obtained by processing the second information/signals in the memory(s) 104 .
  • the memory(s) 104 may be connected to the processor(s) 102 and may store a variety of information related to operations of the processor(s) 102 .
  • the memory(s) 104 may store software code including commands for performing a part or the entirety of processes controlled by the processor(s) 102 or for performing the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document.
  • the processor(s) 102 and the memory(s) 104 may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR).
  • the transceiver(s) 106 may be connected to the processor(s) 102 and transmit and/or receive radio signals through one or more antennas 108 .
  • Each of the transceiver(s) 106 may include a transmitter and/or a receiver.
  • the transceiver(s) 106 may be interchangeably used with Radio Frequency (RF) unit(s).
  • the wireless device may represent a communication modem/circuit/chip.
  • the second wireless device 200 may include one or more processors 202 and one or more memories 204 and additionally further include one or more transceivers 206 and/or one or more antennas 208 .
  • the processor(s) 202 may control the memory(s) 204 and/or the transceiver(s) 206 and may be configured to implement the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document.
  • the processor(s) 202 may process information within the memory(s) 204 to generate third information/signals and then transmit radio signals including the third information/signals through the transceiver(s) 206 .
  • the processor(s) 202 may receive radio signals including fourth information/signals through the transceiver(s) 106 and then store information obtained by processing the fourth information/signals in the memory(s) 204 .
  • the memory(s) 204 may be connected to the processor(s) 202 and may store a variety of information related to operations of the processor(s) 202 .
  • the memory(s) 204 may store software code including commands for performing a part or the entirety of processes controlled by the processor(s) 202 or for performing the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document.
  • the processor(s) 202 and the memory(s) 204 may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR).
  • the transceiver(s) 206 may be connected to the processor(s) 202 and transmit and/or receive radio signals through one or more antennas 208 .
  • Each of the transceiver(s) 206 may include a transmitter and/or a receiver.
  • the transceiver(s) 206 may be interchangeably used with RF unit(s).
  • the wireless device may represent a communication modem/circuit/chip.
  • One or more protocol layers may be implemented by, without being limited to, one or more processors 102 and 202 .
  • the one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP).
  • the one or more processors 102 and 202 may generate one or more Protocol Data Units (PDUs) and/or one or more Service Data Unit (SDUs) according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document.
  • PDUs Protocol Data Units
  • SDUs Service Data Unit
  • the one or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document.
  • the one or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document and provide the generated signals to the one or more transceivers 106 and 206 .
  • the one or more processors 102 and 202 may receive the signals (e.g., baseband signals) from the one or more transceivers 106 and 206 and acquire the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document.
  • signals e.g., baseband signals
  • the one or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers.
  • the one or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof.
  • ASICs Application Specific Integrated Circuits
  • DSPs Digital Signal Processors
  • DSPDs Digital Signal Processing Devices
  • PLDs Programmable Logic Devices
  • FPGAs Field Programmable Gate Arrays
  • the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document may be implemented using firmware or software and the firmware or software may be configured to include the modules, procedures, or functions.
  • Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document may be included in the one or more processors 102 and 202 or stored in the one or more memories 104 and 204 so as to be driven by the one or more processors 102 and 202 .
  • the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document may be implemented using firmware or software in the form of code, commands, and/or a set of commands.
  • the one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, code, instructions, and/or commands.
  • the one or more memories 104 and 204 may be configured by Read-Only Memories (ROMs), Random Access Memories (RAMs), Electrically Erasable Programmable Read-Only Memories (EPROMs), flash memories, hard drives, registers, cash memories, computer-readable storage media, and/or combinations thereof.
  • the one or more memories 104 and 204 may be located at the interior and/or exterior of the one or more processors 102 and 202 .
  • the one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 through various technologies such as wired or wireless connection.
  • the one or more transceivers 106 and 206 may transmit user data, control information, and/or radio signals/channels, mentioned in the methods and/or operational flowcharts of this document, to one or more other devices.
  • the one or more transceivers 106 and 206 may receive user data, control information, and/or radio signals/channels, mentioned in the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document, from one or more other devices.
  • the one or more transceivers 106 and 206 may be connected to the one or more processors 102 and 202 and transmit and receive radio signals.
  • the one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may transmit user data, control information, or radio signals to one or more other devices.
  • the one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may receive user data, control information, or radio signals from one or more other devices.
  • the one or more transceivers 106 and 206 may be connected to the one or more antennas 108 and 208 and the one or more transceivers 106 and 206 may be configured to transmit and receive user data, control information, and/or radio signals/channels, mentioned in the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document, through the one or more antennas 108 and 208 .
  • the one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports).
  • the one or more transceivers 106 and 206 may convert received radio signals/channels etc.
  • the one or more transceivers 106 and 206 may convert the user data, control information, radio signals/channels, etc. processed using the one or more processors 102 and 202 from the base band signals into the RF band signals.
  • the one or more transceivers 106 and 206 may include (analog) oscillators and/or filters.
  • FIG. 34 illustrates another example of a wireless device applicable to the present disclosure.
  • the wireless device may be implemented in various forms depending on use-cases/services (see FIG. 32 ).
  • wireless devices 100 and 200 may correspond to the wireless devices 100 and 200 of FIG. 33 and include various elements, components, units, and/or modules.
  • each of the wireless devices 100 and 200 may include a communication unit 110 , a control unit 120 , a memory unit 130 , and additional components 140 .
  • the communication unit may include a communication circuit 112 and transceiver(s) 114 .
  • the communication circuit 112 may include the one or more processors 102 and 202 and/or the one or more memories 104 and 204 of FIG. 33 .
  • the transceiver(s) 114 may include the one or more transceivers 106 and 206 and/or the one or more antennas 108 and 208 of FIG. 33 .
  • the control unit 120 is electrically connected to the communication unit 110 , the memory 130 , and the additional components 140 and controls the overall operation of each wireless device. For example, the control unit 120 may be control the electric/mechanical operation of each wireless device based on programs/code/commands/information stored in the memory unit 130 .
  • the control unit 120 may transmit the information stored in the memory unit 130 to the outside (e.g., other communication devices) through the communication unit 110 over a wireless/wired interface. Further, the control unit 120 may store information received from the outside (e.g., other communication devices) through the communication unit 110 over the wireless/wired interface in the memory unit 130 .
  • the additional components 140 may vary according to types of the wireless device.
  • the additional components 140 may include at least one of a power unit/battery, input/output (I/O) unit, a driving unit, and a computing unit.
  • the wireless device may be implemented in the form of the robot 100 a ( FIG. 32 ), the vehicles 100 b - 1 and 100 b - 2 ( FIG. 32 ), the XR device 100 c ( FIG. 32 ), the hand-held device 100 d ( FIG. 32 ), the home appliance 100 e ( FIG. 32 ), the IoT device 100 f ( FIG.
  • the wireless device is not limited thereto.
  • the wireless device may be used in a mobile or fixed place depending on use-cases/services.
  • all of the various elements, components, units/portions, and/or modules in the wireless devices 100 and 200 may be connected to each other over a wired interface or at least a part thereof may be wirelessly connected through the communication unit 110 .
  • the control unit 120 and the communication unit 110 may be connected by wire, and the control unit 120 and first units (e.g., 130 , 140 ) may be wirelessly connected through the communication unit 110 .
  • Each element, component, unit/portion, and/or module of the wireless devices 100 and 200 may further include one or more elements.
  • the control unit 120 may be implemented with a set of one or more processors.
  • control unit 120 may be implemented with a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphical processing unit, and a memory control processor.
  • memory 130 may be implemented with a random access memory (RAM), a dynamic RAM (DRAM), a read-only memory (ROM), a flash memory, a volatile memory, a non-volatile memory, and/or any combination thereof.
  • FIG. 35 illustrates a hand-held device applicable to the present disclosure.
  • the hand-held device may include a smartphone, a smartpad, a wearable device (e.g., smartwatch or smartglasses), or a portable computer (e.g., laptop).
  • the hand-held device may be referred to as a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), an advanced mobile station (AMS), or a wireless terminal (WT).
  • MS mobile station
  • UT user terminal
  • MSS mobile subscriber station
  • SS subscriber station
  • AMS advanced mobile station
  • WT wireless terminal
  • a hand-held device 100 may include an antenna unit 108 , a communication unit 110 , a control unit 120 , a memory unit 130 , a power supply unit 140 a , an interface unit 140 b , and an I/O unit 140 c .
  • the antenna unit 108 may be implemented as a part of the communication unit 110 .
  • Blocks 110 to 130 / 140 a to 140 c correspond to the blocks 110 to 130 / 140 of FIG. 34 , respectively.
  • the communication unit 110 may transmit and receive signals (e.g., data and control signals) to and from other wireless devices and/or base stations.
  • the control unit 120 may perform various operations by controlling components of the hand-held device 100 .
  • the control unit 120 may include an application processor (AP).
  • the memory unit 130 may store data/parameters/programs/code/commands required to drive the hand-held device 100 .
  • the memory unit 130 may store input/output data/information.
  • the power supply unit 140 a may supply power to the hand-held device 100 and include a wired/wireless charging circuit, a battery, etc.
  • the interface unit 140 b may support connections between the hand-held device 100 and other external devices.
  • the interface unit 140 b may include various ports (e.g., audio I/O port, video I/O port, etc.) for the connections with the external devices.
  • the I/O unit 140 c may input or output video information/signals, audio information/signals, data, and/or information input by a user.
  • the I/O unit 140 c may include a camera, a microphone, a user input unit, a display unit 140 d , a speaker, and/or a haptic module.
  • the I/O unit 140 c may obtain information/signals (e.g., touch, text, voice, image, video, etc.) input by a user, and the obtained information/signals may be stored in the memory unit 130 .
  • the communication unit 110 may convert the information/signals stored in the memory unit 130 into radio signals and transmit the converted radio signals to another wireless device directly or to a base station.
  • the communication unit 110 may receive radio signals from the other wireless device or the base station and restore the received radio signals to original information/signals.
  • the restored information/signals may be stored in the memory unit 130 and output in various forms (e.g., text, voice, images, video, haptic, etc.) through the I/O unit 140 c.
  • FIG. 36 illustrates a vehicle or an autonomous driving vehicle applicable to the present disclosure.
  • the vehicle or autonomous driving vehicle may be implemented as a mobile robot, a car, a train, a manned/unmanned aerial vehicle (AV), a ship, etc.
  • AV manned/unmanned aerial vehicle
  • a vehicle or autonomous driving vehicle 100 may include an antenna unit 108 , a communication unit 110 , a control unit 120 , a driving unit 140 a , a power supply unit 140 b , a sensor unit 140 c , and an autonomous driving unit 140 d .
  • the antenna unit 108 may be configured as a part of the communication unit 110 .
  • the blocks 110 / 130 / 140 a to 140 d correspond to the blocks 110 / 130 / 140 of FIG. 34 , respectively.
  • the communication unit 110 may transmit and receive signals (e.g., data and control signals) to and from external devices such as other vehicles, base stations (e.g., gNBs and road side units), and servers.
  • the control unit 120 may perform various operations by controlling elements of the vehicle or the autonomous driving vehicle 100 .
  • the control unit 120 may include an Electronic Control Unit (ECU).
  • the driving unit 140 a may cause the vehicle or the autonomous driving vehicle 100 to drive on a road.
  • the driving unit 140 a may include an engine, a motor, a powertrain, a wheel, a brake, a steering device, etc.
  • the power supply unit 140 b may supply power to the vehicle or the autonomous driving vehicle 100 and include a wired/wireless charging circuit, a battery, etc.
  • the sensor unit 140 c may acquire a vehicle state, ambient environment information, user information, etc.
  • the sensor unit 140 c may include an Inertial Measurement Unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor, a heading sensor, a position module, a vehicle forward/backward sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illumination sensor, a pedal position sensor, etc.
  • IMU Inertial Measurement Unit
  • the autonomous driving unit 140 d may implement technology for maintaining a lane on which a vehicle is driving, technology for automatically adjusting speed, such as adaptive cruise control, technology for autonomously driving along a determined path, technology for driving by automatically setting a path if a destination is set, and the like.
  • the communication unit 110 may receive map data, traffic information data, etc. from an external server.
  • the autonomous driving unit 140 d may generate an autonomous driving path and a driving plan from the obtained data.
  • the control unit 120 may control the driving unit 140 a such that the vehicle or the autonomous driving vehicle 100 may move along the autonomous driving path according to the driving plan (e.g., speed/direction control).
  • the communication unit 110 may aperiodically/periodically acquire recent traffic information data from the external server and acquire surrounding traffic information data from neighboring vehicles.
  • the sensor unit 140 c may obtain a vehicle state and/or surrounding environment information.
  • the autonomous driving unit 140 d may update the autonomous driving path and the driving plan based on the newly obtained data/information.
  • the communication unit 110 may transfer information about a vehicle position, the autonomous driving path, and/or the driving plan to the external server.
  • the external server may predict traffic information data using AI technology, etc., based on the information collected from vehicles or autonomous driving vehicles and provide the predicted traffic information data to the vehicles or the autonomous driving vehicles.
  • FIG. 37 illustrates a vehicle applicable to the present disclosure.
  • the vehicle may be implemented as other transport means such as a train, an airplane, a ship, etc.
  • a vehicle 100 may include a communication unit 110 , a control unit 120 , a memory unit 130 , an I/O unit 140 a , and a positioning unit 140 b .
  • the blocks 110 to 130 / 140 a to 140 c correspond to the blocks 110 to 130 / 140 of FIG. 34 , respectively.
  • the communication unit 110 may transmit and receive signals (e.g., data and control signals) to and from external devices such as base stations or other vehicles.
  • the control unit 120 may perform various operations by controlling components of the vehicle 100 .
  • the memory unit 130 may store data/parameters/programs/code/commands for supporting various functions of the vehicle 100 .
  • the I/O unit 140 a may output an AR/VR object based on information within the memory unit 130 .
  • the I/O unit 140 a may include an HUD.
  • the positioning unit 140 b may acquire information about the position of the vehicle 100 .
  • the position information may include information about an absolute position, a position on a driving lane, acceleration, and a relative position with respect to a neighboring vehicle of the vehicle 100 .
  • the positioning unit 140 b may include the global positioning system (GPS) and various sensors.
  • GPS global positioning system
  • the communication unit 110 of the vehicle 100 may receive map information and traffic information from an external server and store the received information in the memory unit 130 .
  • the positioning unit 140 b may obtain vehicle position information from the GPS and various sensors and store the obtained information in the memory unit 130 .
  • the control unit 120 may generate a virtual object based on the map information, traffic information, and vehicle position information, and the I/O unit 140 a may display the generated virtual object on a window in the vehicle ( 1410 and 1420 ).
  • the control unit 120 may determine whether the vehicle 100 normally drives on a driving lane based on the vehicle position information. If the vehicle 100 gets out of the driving lane irregularly, the control unit 120 may display a warning on the window in the vehicle through the I/O unit 140 a . In addition, the control unit 120 may broadcast a warning message about irregular driving to neighboring vehicles through the communication unit 110 . In some cases, the control unit 120 may transmit the vehicle position information and information about abnormality in the driving/vehicle to involved departments.
  • the implementations of the present disclosure are applicable to various wireless access systems including 3GPP and/or 3GPP2.
  • the implementations of the present disclosure are also applicable not only to the various wireless access systems but also to all technical fields in which the wireless access systems find their applications.
  • the proposed methods may be applied to mmWave communication systems based on ultra-high frequency bands.
  • implementations of the present disclosure are further applicable to various applications such as autonomous driving vehicles, drones, etc.
US17/267,472 2018-08-09 2019-08-09 Method for operating terminal and base station in wireless communication system supporting NB-IoT, and apparatus supporting Active 2041-02-07 US11956754B2 (en)

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US201862716890P 2018-08-09 2018-08-09
KR20180114495 2018-09-21
KR10-2018-0114495 2018-09-21
US201862760876P 2018-11-13 2018-11-13
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KR20190018101 2019-02-15
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